It started with Sherlock Holmes.

He's one of those people without whom forensic science would not exist.

Holmes was so far ahead of his time.

That's what's so cool about him, is that he is the first to use these same techniques that we use 120 years later.

Sherlock Holmes, I consider him as the grandfather of forensic science.

When I go to a crime scene I use his logic, solving cases.

Sherlock Holmes was the one to give law enforcement the idea to look at something with a magnifying glass, to look for things that you couldn't see.

Which is still one of my favorite tools today, my magnifying glass.

I go nowhere without it.

I wonder what Holmes would think about the state-of-the-art, the cutting edge technology that we have today.

In my view of Holmes, he'd probably say, "What took you so long?"

Sherlock Holmes, the greatest ever fictional detective,   worshiped by police the world over   as the man who taught them how to solve crimes.

Sherlock Holmes was the first   to protect crime scenes from contamination,   the first detective to look for minute evidence and traces,   to search for what the eye couldn't see,   to sniff...   ..to measure, to make astonishing deductions.

The murderer was a man.

He had small feet for his height.

He wore coarse, square-toed boots and smoked a Trichinopoly cigar.

From blood to ballistics,   to fingerprints, footprints and poison,   Sherlock Holmes was 120 years ahead of his time.

Without the inspiration of Sherlock Holmes, I wouldn't be a forensic scientist and I wouldn't have solved the cases that I've solved.

Sherlock transformed the world of crime investigations   and, over a century later,   this fictional detective is still helping to solve crimes.

(man)   This murder was very much a case that could be a perfect Sherlock Holmes adventure.

It got me really to understand how Sherlock Holmes was so much like modern-day forensic scientists.

Because of this careful observation, based on Sherlock Holmes's logic, we was able to solve the case.

When Sherlock first burst onto the scene in Victorian England,   the police certainly needed his help.

London.

The last day of August, 1888.

The day one of history's most notorious serial killers   claimed their first victim.

(woman) &nbspPeople are worried, scared.

There's a killer out and even though he's targeting prostitutes, it still doesn't mean everybody's safe.

It was the first of what became known as   the Jack the Ripper murders.

He did six murders within a mile in less than 90 days.

As the terrible killings continued,   the ineptitude of the police's then standard   investigative methods became clear.

Little or no evidence was collected   from the crime scenes,   which were quickly contaminated by police and onlookers.

(Karen)   Back then, there was no crime scene contamination.

A crime scene was just a crime scene and whoever needed to be inside of it went.

There was no picking over the scene.

They weren't doing anything like Sherlock.

The focus was still trying to find an eyewitness.

(Richard)   Evidence?

What do you mean, evidence?

(laughs) They would leave mountains of it around, not recognizing what it was.

Arthur Conan Doyle was still a young eye doctor   when he published the first Sherlock story,   just a few months before the Ripper murders began.

Sherlock's cutting edge evidence gathering   was in stark contrast to what the police were doing.

That was the focus of the Sherlock Holmes stories, this evidence that, in most criminal cases, was not being gathered.

All these things were foreign concepts to police at the time.

They were not there to be thinkers.

They were not there to be evidence gatherers or interpreters.

Forensic science did not even exist.

Criminal investigation consisted essentially of rounding up the usual suspects and getting confessions from them, to be quite blunt.

We're talking brawn, not brains.

Sherlock was about to change the world forever,   first in fiction, then in fact.

But it was too late to catch Jack the Ripper,   leaving the most iconic crime of the last 200 years unsolved.

The one prostitute that was found in the room with the blood pattern evidence, with all of the other evidence left, perhaps with shoe prints that were left because there was so much blood in that scene, perhaps Holmes could have come in and deduced something a little bit different.

Maybe he could have seen something a little bit differently.

Those murders could have used a lot more Sherlockian technique.

But from the very first Sherlock adventure,   Sir Arthur Conan Doyle was unwittingly writing   the world's first forensic science manual.

(Karen) A Study in Scarlet was the first book that I read when I started crime scene investigations and I thought, "This is really relevant, 120 years later."

"A Study in Scarlet" gave birth to the great detective.

He was arrogant... My dear Lestrade, I've investigated many crimes, but I have yet to see one which has been committed by a flying creature.

..eccentric,...   ..clever...

So long as the criminal remains upon two legs, so there must be some indentation, abrasion, trifling displacement which may be found by the scientific searcher.

..and a pioneering chemist...

If this paper remains blue, all is well.

If not... it means a man's life.

Catching the spirit of the age   of scientific inquiry and discovery,   the public couldn't get enough of Sherlock Holmes's adventures   and the stories rapidly became best sellers.

(Brent)   Conan Doyle's mission is to educate people to say, "This is how scientific investigations ought to be done."

Sherlock Holmes was a mechanism for delivering this idea that physical evidence was important.

It's almost like reading a manual for investigation.

That search for competence, for integrity, for thoroughness, that's the story that Conan Doyle wants to tell, because that's what he wants people to emulate.

The first Sherlock Holmes story, "A Study in Scarlet,"   is a master class in how Sherlock changed the world   of forensic science.

A body has been discovered,   and bemused police ask for Sherlock's help.

Ah, Inspector Lestrade.

With men such as you upon the ground, there won't be much left for a third party like me to find out.

I think we've done all that can be done.

It's a queer case, though, and I knew your taste for such things.

The techniques Sherlock uses on the crime scene   are the first dazzling appearance   of forensic crime solving,   both in fiction and, largely, in real life as well.

Sherlock Holmes is still an inspiration, especially to me, today.

Walking into a crime scene can be very overwhelming and it's sometimes really hard to rein yourself in.

Having his deductive powers really can help give you an idea of not only where to start, but where to go.

(Kimberlee)   Sherlock's approach to the crime scene was cutting edge.

He gets right down to the floor and he looks at the way the light hits the floor and he can see footprints.

You know, that was just revolutionary.

No one would have done that.

No one had even begun to think in those terms.

(Karen)   He would get right over a piece of evidence and study it with his magnifying glass, which is still one of my favorite tools today, my magnifying glass.

I go nowhere without it.

Nowhere.

That's what's so cool about him, is that he is the first to use these same techniques that we use 120 years later.

He smelled things that nobody wanted to smell.

Back then, nobody had ever seen that done before.

I'm sure what Sherlock was doing at a crime scene seemed very odd to Watson, to the police officers at the time, because they weren't used to looking in unusual places for unusual types of evidence and would have thought, "There's nothing we can get with that."

For the very first time,   Sherlock was gathering what we now know as forensic evidence.

Forensic evidence is the only part of a case that doesn't lie.

It's the only part of a case we can rely on to tell the truth and Holmes knew that, whether it be a shoe print or a hair or a cigar ash.

Sherlock's art of looking at the whole crime scene,   combing it meticulously   for whatever evidence there might be,   changed the world of investigations.

Police at the time were perplexed   by Sherlock's startling new approach   to crime scene investigations,   but today's detectives say Sherlock's lessons taught them   that even the most unlikely piece of evidence   can turn out to be of massive importance.

When we look over the crime scene, I get down and look and maybe seven, eight feet away, I find this button.

The other agents say, "Oh, that's nothing."

"Who does he think he is, Sherlock Holmes?"

But the next day, the agents, they had a suspect and when they're talking to him, they see he's missing a button.

They bring him back to the office.

"Bill, you got that button?"

I said, "I sure do."

"See if it fits on his coat," and, sure enough, it did.

And the man just caved and started helping us with the rest of the case and we locked up a lot of people from the button, and that's when you get them, and that's the rule of evidence.

That's what Holmes told you to look for.

And in "A Study in Scarlet,"   a similarly small piece of evidence   will go on to help Sherlock solve the case.

Although typically,   Inspector Lestrade goes barking up the wrong tree.

There's been a woman here.

It's a woman's wedding ring.

Well, this complicates matters.

Heaven knows, they were complicated enough before.

Really, Inspector?

You sure it doesn't simplify them?

Using evidence like this   to gradually piece together the puzzle   made Sherlock's adventures gripping reading   and struck a chord with the wider public.

(man)   When you read a Sherlock Holmes novel, you are in the same position as Sherlock Holmes.

You are presented with the same facts, the same world, the same characters and you have to follow in his footsteps, observing the same clues.

In that very first novel,   A Study in Scarlet, you realize that there is something happening between you and the page and you and the character and there's a sort of spark going on there and you follow that spark where it takes you.

"In this particular corner of the room,   across a bare space there was scrawled in blood-red letters   a single word..."   "..'Rache.'"

When a piece of evidence is discovered,   the police, in the form of Inspector Lestrade,   are quick to jump to conclusions,   much to the amusement of Sherlock Holmes.

(Lestrade)   That disposes of the idea of suicide, anyhow.

And what does it mean, now that you've found it?

Mean?

Well, it means the writer was going to put the female name "Rachel," but was disturbed before he or she could finish.

You mark my words, this case is almost cleared up and you'll find a woman named Rachel has something to do with it.

(Holmes) It is a capital mistake to theorize   before you have all the evidence.

It biases the judgment.

One should not theorize and develop a theory before having facts, all the facts, and Sherlock Holmes would say that it's the bane of our profession.

Oh, it's all very well for you to laugh, Mr. Sherlock Holmes.

You may be very smart and clever, but the old hound is the best, when all is said and done.

They say that genius is an infinite capacity for taking pains.

It's a very bad definition, but it does apply to detective work.

Come along, doctor.

For Sherlock, gathering the evidence   is only half the story.

His genius was to teach detectives   what to infer from it,   how to put the evidence together,   building up a picture of the crime and the murderer.

Oh, Inspector Lestrade, I'll tell you one thing which may help you in this case.

There has been murder done and the murderer was a man.

He was more than six feet high.

He was in the prime of life.

He had small feet for his height.

He wore coarse, square-toed boots and smoked a Trichinopoly cigar.

In all probability, the murderer had a florid face and the fingernails of his right hand were remarkably long.

These are only a few small indications, but they may assist you.

If this man was murdered, how was it done?

Poison.

Oh, and one other thing...   "Rache"   is the German for revenge, so don't lose your time looking for Miss Rachel.

Deductive reasoning,   how Sherlock works out the puzzle of a crime,   is the most timeless of his gifts to the world   and it's a skill shown off to a new generation   in the BBC's much lauded series "Sherlock."

The killer's not left us much, just the shirt and the trousers.

They're pretty formal...   Deductive reasoning is the process of using evidence   to reach a logically certain conclusion.

They're both too big for him, so a standard issue uniform.

Dressed for work.

What kind of work?

There's a hook on his belt for a walkie talkie.

- Tube driver?

- Security guard?

Likely.

That'll be borne out by his backside.

Backside?

It's a skill as vital today   as when Sherlock first brought it to the world's attention.

- His legs show otherwise.

- Fantastic.

- Meretricious.

- And a happy new year.

Sherlock Holmes transformed investigations   from relying on confessions and eyewitness accounts   to a world where evidence and deduction were paramount.

It's a journey one of America's top forensic scientists,   Dr. Henry Lee, has himself traveled.

(Henry)   I joined the police force in Taiwan.

At that point in time, in 1960, we still using interrogation technique.

Round up the usual suspect until one confess.

If nobody confess, you take them to the back room.

We used to encourage water hose, black jack, so everybody confessed, so the case is solved.

You really don't know you solved the case or just force him to confess.

But Dr. Lee was an avid "Sherlock Holmes" reader   and, by the time he was appointed   Chief State Criminalist for Connecticut in the '70s,   he was being hailed as the modern-day Sherlock Holmes.

(Henry)   I remember when I read Sherlock Holmes story, he approached a scene with a open mind.

He used physical evidence, collect the evidence, tries, through this deductive logic, tries to put the case together.

Many of Dr. Lee's investigations   have hinged on blood evidence,   not least a mysterious murder case in Florida   where all was not as it seemed.

Police were called to the scene   where they found the body of 46-year-old Stephen Haines,   naked and face down in a garage.

Haines's live-in partner, Suzan Barratt,   had discovered his bruised body amidst a bloody scene.

Three days later,   Barratt was charged with second-degree murder.

She confessed to fatally striking Haines   with a wine bottle during an argument.

(scuffling sound effects)   (glass smashes)   But Barratt's lawyer harbored deep suspicions   that her confession was false   and had been extracted under duress.

He contacted the only person   besides the great detective himself who could help.

(Henry) &nbspI went to the crime scene.

Blood all over the place.

So obviously violent active scene.

They jumped at conclusion, that's a homicide, without check the detail.

I said, "Why don't we use Sherlock Holmes's logic?"

Now, that could be a homicide.

Could be a suicide and could be a staging, could be even a accident.

So, yeah, if you walk in the scene, definite it's a homicide, and this person look guilty, therefore this individual killed this victim.

That's jump to the conclusion.

Now we have to have a open mind, have different possibilities.

When you eliminate all the impossible, whatever's remain become more probable.

Examining the blood evidence at the scene,   Dr. Lee was immediately drawn to the spots on the floor.

(Henry)   Regular blood drop touch the surface from a certain height, leave a certain size, usually circular.

I look at those blood spot.

One, they had no center, just the periphery area had blood, center lack of blood.

Those type of pattern I call ghost center or a holey spot... blood drops.

That indicate to me more likely... the individual vomiting blood, coughing the blood.

That individual's blood mixed with air.

During the drying process, the air bubble busted, that's why it leave a holey center.

Now, Mr. Haines loved to drink and often get drunk.

Most chronic alcoholic people have liver cirrhosis, so the blood sometime get to their lung and they vomit it out.

So at the crime scene, when we see those pattern, I can reach a conclusion.

That's because chronic alcoholics are vomiting blood.

In addition, I looked at a autopsy picture.

The 170 some injury or bruises, no open cut.

I suggest the lawyer search all the hospital records for now in that period of time ambulance been called 15 times.

Every time he got drunk, he bump into tables, bureaus and cause all those bruises.

Not really a spouse abuse.

I was able to show Haines died of chronic alcoholism, which the prosecutor agree and the judge agree and the case was dismissed.

Because this careful observation based on Sherlock Holmes's logic, we was able to eliminate homicide as a cause.

If you read every Sherlock Holmes story, it's a puzzle.

Each, every one, he just pieces together, so taught us a valuable lesson.

Every case, you should have a open mind and try to put the puzzle together.

In "A Study in Scarlet,"   Sherlock masterfully puts the pieces together   and catches the murderer.

The case closed, Sherlock explains his method   not just to his sidekick Watson,   but to millions of avid readers, both then and now.

In solving a problem of this sort, the grand thing is to be able to reason backward, but not many people practice it.

Now, this is a case where you were given the result and had to work out everything else for yourself.

Each element of Sherlock's deductive reasoning   became a blueprint for future detectives   and forensic scientists.

Sherlock's deduction is a matter of trying to work out why things now appear as they are.

Trying to work back to what possible actions may have resulted in the evidence that we see now.

We approached this case, if you remember, with an absolutely blank mind.

We had formed no theories.

We were simply there to observe.

He went in with a clean slate, with a blank mind, not having any preconceptions of what may or may not have happened, and you still have to do that today, no matter how much information is coming at you.

To theorize prior to getting there is like fitting a square peg in a round hole.

Surely you're not as sure as you pretended to be of all those particulars which you gave Inspector Lestrade?

Oh, Inspector Lestrade, I'll tell you one thing which may help you.

The murderer was a man.

He was more than six feet high.

He was in the prime of life.

He had small feet for his height.

He wore coarse, square-toed boots and smoked a Trichinopoly cigar.

He's looking at these minute traces, these minute details, these minute choices that will tell you something about maybe the height of the offender, their shoe size, their weight, all these little details he's looking at to help infer something about the offender, and that is the essence of criminal profiling.

(Holmes)   There is no room for a mistake.

Why, it was easy for me to tell that the nocturnal visitors were two in number.

One, remarkable for his height, which I had told from the length of his stride, the other, fashionably dressed, judged from the small and elegant impression left by his boots.

On observation of the body, the well-booted man lay before me.

The tall one, then, had done the murder.

Sherlock Holmes represents the first time that we're using scientific investigation and physical evidence to deduce offender characteristics.

There is no mystery about it all.

Is there anything else that puzzles you?

My head is a whirl.

The more one thinks on it, the more mysterious it grows.

Why did the second man write up the German word  "Rache?"

The question of every piece of evidence is does it fit with your theory of the crime?

Does it make sense?

And if it doesn't, what are the alternate explanations?

That was one thing that Sherlock Holmes was very good at, is examining those little details and seeing if they fit into the big picture of the crime.

My dear doctor, the writing was merely a blind, intended to put the police upon a wrong track.

It was not done by a German.

The "A," if you notice, was printed somewhat after the German fashion.

A real German invariably prints after the Latin character.

I confess, I cannot see any possible way of reconciling all these facts.

Sherlock then deduced that the murderer   had cruelly compelled his victim to take poison.

There was no wound upon the dead man's person, but the fear and hatred on his face led me to believe that he had foreseen his fate well before it had come upon him.

Having sniffed the dead man's lips, I detected a slightly sour smell.

This made me come to the conclusion that he had had poison forced upon him.

Now we come to the great question as to the reason why.

It must have been a private wrong, to call for such a methodical revenge.

When the ring was discovered, it settled the question.

Clearly, the murderer used it to remind his victim of some lost or absent woman.

It is an old maxim of mine that, once you've excluded the impossible, whatever remains, however improbable, must be the truth.

By this method of exclusion, I had arrived at this result and no other hypotheses would meet the facts.

(Karen)   My favorite quote from Sherlock Holmes is, "When the impossible is excluded, what remains is what happened," and that's very true in all kinds of crime scene investigations.

If we lose the deductive reasoning that Sherlock had, we'll lose the case.

Period.

(Kimberlee)   You could equate blood with life.

Blood is a very interesting substance, the way that it reacts, the way that it looks.

It fluoresces under certain types of lighting.

You know, there is a lot of blood in the human body.

The fact that we are so dependent on so much of it.

If you find blood at a crime scene, something bad has happened here.

Today, investigators can extract DNA from blood,   matching it to a single individual.

When Conan Doyle started writing   the Sherlock Holmes stories in 1886,   there was no definitive test for confirming a spot   was actually blood at all.

It could be explained away as something else by the accused.

The scientific challenge of the age   was to produce a test that would prove it.

Forensic science in the 1890s didn't exist as a discipline.

There were no forensic science laboratories in the world.

It was really very early days.

The first forensic science lab in the UK was in 1935, so 1890s is a long way earlier than that.

But there was one forensic lab   in the front room of 221B Baker Street,   where Sherlock Holmes himself   was working on a definitive test for human blood.

It is the most practical medico-legal discovery for years.

It gives us an infallible test for blood stains.

Come here now.

Let us have some fresh blood.

Now, I add this blood... ..to this liter of water and we'll see the resulting mixture has the appearance of pure water.

A-ha!

What do you think of that?

Seems a very delicate test.

Beautiful.

Beautiful.

The old Guaiacum test was very clumsy and uncertain.

So was the microscopic examination for blood corpuscles.

Now, this appears to work as well, whether the blood is old or new.

Had this test been invented, there are now hundreds of men walking the Earth who would long ago have paid the penalty of their crimes.

Indeed.

Now we have the Sherlock Holmes test and there will no longer be any difficulty.

People reading this must have seen it as science fiction and found that it was almost incredible and extraordinary and that perhaps sometime in the distant future, maybe scientists would be able to develop these tests or be able to come to these same conclusions, but surely these were all just fantastic ideas.

Although fictional, Sherlock's leaps in investigative science   spurred scientists to do it for real.

Thirteen years later, in 1900,   Professor Paul Uhlenhuth developed   the first ever definitive test for human blood.

Today, it has become a routine tool   in crime scene investigations.

(Karen) &nbspFor me, it's very simple.

I pull out my portable test and I get a positive reaction, I know it's blood.

If I get a negative, I know it's not.

Well, back then... any old brown spot, what are you going to do with it?

Holmes did a blood test.

That fiction became fact... and we still use it today.

Sherlock Holmes himself was hugely influential   in his abilities to use blood evidence   in deducing many details about a crime scene.

Well, there's some blood staining here.

Yes, sir.

I picked that book off the floor.

Was the blood stain above or below?

On the sides, next to the boards.

(Holmes)   Which proves the book was dropped afterwards.

I conjecture it was dropped by the murderer in his hurried flight.

Karen Smith is one of America's top crime scene investigators.

This female Sherlock has investigated   20,000 crime scenes, over 500 deaths   and is an expert in blood spatter analysis.

A very Sherlockian application of blood spatter analysis   became a surprising and decisive element   in one of America's most notorious murder trials,   that of Dr. Sam Sheppard.

On July 4, 1954, in their home in Bay Village, Ohio,   Dr. Sam Sheppard's pregnant wife Marilyn   was found murdered.

The crime scene in the Dr. Sam Sheppard case was one of the most convoluted, chaotic crime scenes and it still fascinates me to this day.

Dr. Sam Sheppard was accused of murdering his wife Marilyn in their home in Ohio.

She was found in her bed, face up.

Her legs had been pulled underneath the foot of the bed railing and she had been bludgeoned to death.

Her top had been pulled up, her bottoms had been pulled down and she was left there with part of a sheet covering her mid-section.

The good doctor said that he had been sleeping on the daybed downstairs and he awoke to find an intruder in the home, which he described as a... form that bludgeoned him in the head and he lost consciousness.

When he came to, the form was in his house and he chased it down onto the beach behind their house, down this very steep stairwell, down a rocky embankment, down to the beach, fought the attacker again down on the beach, lost his shirt in the process, became completely wet, saturated himself, at which point he was knocked unconscious again on the beach, came to, went back upstairs to the house, where he then went upstairs and found Marilyn dead in bed and then alerted the police.

Crazy crime scene.

The suspicion was that Dr. Sheppard's story,   of a mysterious form that he fought with on the beach,   was a lie to cover up that he'd murdered Marilyn,   destroyed his blood-stained shirt   and cleaned himself of blood.

(Brent) &nbspOne thing that's alleged is that there was an intruder who was alleged to have also tried to rob the home of valuables and, to that end, the intruder was alleged to have rifled through a desk in the downstairs area, during which time items got knocked on the floor and broken, and this was evidence ostensibly of a home invasion with a robbery.

On close inspection, however, nothing was actually taken from that area and harkening back to me that Sherlock Holmes would look at this case as what makes sense?

What actually happened?

What would be the outcome of these things?

He did not remember a whole lot and, when he took the stand in his own defense, which he did, a lot of it was, "I don't recall because I was knocked unconscious."

It was very vague.

Dr. Sam Sheppard was convicted of his wife's murder   and sentenced to life imprisonment.

But his legal team brought in a specialist   to reinvestigate the case,   leading forensic scientist Dr. Paul Kirk.

(Brent)   He's a big guy in the world of science and one of the only private forensic scientists in the country, so a huge name in forensic science.

Dr. Paul Kirk was a leader in forensic science, especially in blood pattern analysis.

He wrote all kinds of papers.

They're still used today.

So he was definitely a frontrunner back in the day.

Like Sherlock Holmes, Paul Kirk was all about examining trace evidence, examining small bits of evidence to connect people to crime, examining patterns and considering the big picture to figure out what exactly happened.

Using that Holmes whole-scene approach, what Kirk did is he looked at the entire house.

He looked at the beach, he looked at the photos, he looked at the bedroom where it happened, including all of the walls, the ceiling, the floor, the radiator, the closet doors.

Just as Sherlock had done in fiction,   Dr. Kirk concentrated on the minute detail   and found something that had been missed at the first trial,   blood spatter.

If you look at the spatter pattern I created, these blood droplets here were direct impact at a 90-degree angle.

They came straight into the wall this way.

As you travel this direction, you can see they become oval.

They also have tails, and the tails are indicative of the direction the blood was traveling when it impacted the wall, so as we follow this direction you can see the more elongated the shapes become, and that's because they're hitting the wall at a sharper angle.

They also travel in an arc all the way down toward the floor and once they hit the floor, they once again turn into a circle because they're impacting again at a 90-degree angle toward the floor.

What he did is he looked at the blood spatter patterns on the ceiling and walls and there's a certain type of spatter pattern called a cast-off.

Cast-off is when blood is flung off a weapon... ..onto a substrate.

Cast-off allowed Dr. Kirk to tell the number of blows struck   and what direction they came from.

But Dr. Kirk was certain   the blood evidence could tell him more.

He realized that there was an area in the room that was lacking the same patterns as the rest of the room.

It's called a void pattern, where blood should be but isn't.

So he deduced that the person that was blocking it had the blood on them and on the weapon.

Instead of it going behind them on the wall, it landed on their person, and that's where the perpetrator must have been standing when he or she committed this heinous act.

By meticulous examination   of both the cast-off and void blood patterns,   in true Sherlockian style   Dr. Kirk was able to make an extraordinary deduction   about the murderer.

He placed the weapon in the left hand and realized, if you go back with the left hand... you're going to leave a certain arc pattern on the ceiling and the wall behind you.

If you place it in the right hand and do the same motion, it's obviously going to leave a different pattern on the ceiling in a different portion of the ceiling and wall.

If you place it in the right hand and you do a cross body, you can see the arc pattern would be completely different and would be dispersed further away and at a sharper angle than it would have been if it was a straight-on left-hand shot over the shoulder.

And, with deductive reasoning, as Holmes would have done, he deduced that the perpetrator must have been left-handed.

Paul Kirk's finding changed the whole course of events.

Dr. Sam Sheppard was right-handed.

In a subsequent retrial,   Sam Sheppard was acquitted of all charges.

Sherlock's unique deductive thinking influenced Kirk   and generations of investigators.

But where did the great detective's   incredible powers of reasoning come from in the first place?

In the late 1870s,   Arthur Conan Doyle studied medicine in Edinburgh.

His tutor and mentor was one of the great minds of the age   and an astonishing trailblazer in deductive thinking.

I used, as a student, to have an old professor, his name was Bell, who was extraordinarily quick at deductive work.

He would look at the patient, he would hardly allow the patient to open his mouth, but he would make his diagnosis of the disease, and also very often of the patient's nationality and occupation and other points, entirely by his power of observation.

(Anthony Horowitz)   Dr. Joseph Bell made a profound impression upon the young Arthur Doyle.

He was apparently able to identify a patient as a recent soldier, somebody out of a regiment that had served in Barbados, and he knew it by two observations.

The first was that the man didn't take his hat off when he came into the room, which a soldier recently retired wouldn't have been expected to do; he'd have kept his hat on, so although the man was polite, he kept his hat on, therefore he's a soldier.

He was also suffering from elephantiasis and elephantiasis was a disease which, at that time, was raging in Barbados, ergo he's a soldier from Barbados.

Pure Holmes.

Pure Holmes.

Please, Mr. Holmes, where you're going you'll want to be dressed.

I know exactly where I'm going.

Years before he created Holmes,   Doyle had always been fascinated   by Dr. Bell's deductive powers.

(Dr. Bell) &nbspDoyle was always making notes.

He seemed to want to copy down every word I said.

Many times after a patient departed my office, he would ask me to repeat my observations so that he would be certain he had them down correctly.

I always regarded him as one of the best students I had.

He never tired of trying to discover all those details which one looks for.

Joseph Bell had a style of medicine that required people to observe and to notice, not just to look, but to observe, to look at details and say that the details would actually lead you to many answers that you would otherwise overlook.

Dr. Bell's uncanny abilities went on to be shared   by the great fictional detective.

So naturally, I thought to myself, "Well, if a scientific man like Bell was to come into the detective business, he wouldn't do these things by chance."

"He'd get the thing by building it up scientifically."

(Brent)   It's a very compelling story and it's also a skill set that he saw absent from law enforcement and criminal investigation at the time.

So for him it's a journey of trying to explain that this skill set does exist, it is achievable, I know somebody who's like this and let me bring this person to life and maybe have an impact.

In the 1880s, the police knew next to nothing   about ballistics evidence,   where a bullet was fired from or matching it to the gun.

But Sherlock was already ahead of the game.

It was almost 40 years before the FBI   took Sherlock's work further, matching bullets to guns   after the notorious St Valentine's Day Massacre.

But in Sherlock's time, with ballistics in its infancy,   the great detective was way ahead.

In Sherlock's case of "The Reigate Squires,"   a man has been shot and killed,   allegedly at close quarters during a struggle.

But Sherlock's observation of the body   immediately leads him to a different explanation.

(Holmes)   The wound upon the dead man was, as I was able to determine with absolute confidence, fired from a revolver at the distance of over four yards.

What Sherlock's able to do is determine that their claim that they were fighting at close quarters is invalid.

(Holmes)   I could see no trace of powder blackening on the clothes.

(man) &nbspHe does that by observation of gunpowder soot deposit or, rather, the lack of it.

Guns discharge, particularly black powder firearms, discharge an awful lot of soot, what most people know as powder burns.

In fact, there is burning at very close range.

Beyond that, there's a projection of this black sooty deposit.

That discharge becomes undetectable, certainly to the human eye, and from that he confidently pronounces, using his observational and deductive abilities, that the firearm must have been discharged from over four yards away and this was a straightforward shooting.

(Holmes)   Evidently, therefore, Alec Cunningham had lied when he said that the two men were struggling when the shot was fired.

Pre-dating the advanced forensic science of ballistics,   just how accurate was Sherlock's deduction   that the absence of powder blackening   meant the shot was from four yards away?

(man)   We'll use a vintage revolver from the period of Sherlock Holmes, which is about 1892.

We'll fire a few shots, we'll start off at about a foot, then move further away and we'll have a look and see where the powder blackening stops.

At very close range, plenty of powder is transferred.

The next shot is from two feet back.

(Andre) &nbspIt's clearly still visible.

You could definitely tell that this shot was fired from a further distance than the first one, but you can still see that it was a close-range shot.

At three feet, the blackening is falling off,   but still visible.

I think we'll go back and try two yards.

And at two yards, we basically have a clean sheet.

If anything, Holmes's estimate of four yards was generous,   but he did show it was possible   to calculate the distance a gun was fired from.

(man)   Sherlock anticipates the abilities that modern forensic science has, that we can actually now convict criminals on the basis of scientific evidence.

And Sherlock was there at the beginning, doing that in fiction.

But he was also quite eerily prescient about this, because the very same year that the case of  The Reigate Squire was published, the Ardlamont mystery took place on an estate in Argyllshire in Scotland.

In August 1893, tutor Alfred John Monson   took Cecil Hambrough, his 20-year-old pupil,   hunting on the Ardlamont Estate in Argyll, Scotland.

Estate workers heard a shot,   then saw Monson running to the house.

He said his young pupil had accidentally been shot dead.

The boy was found dead.

He had been trying to climb over a fence.

The gun became hung up on something and discharged and it killed him.

It sounds very Holmesian, but who should be drafted in to help Crown's evidence but Dr. Joseph Bell.

Dr. Bell was Scotland's most eminent surgeon   and the living inspiration for Sherlock Holmes.

The great detective shared Bell's powers of deduction.

Bell resolved to carry out test firing   to see at what distance he could recreate   the allegedly close-range wound.

Bell was satisfied that it was impossible for a shot to have been fired at anything less than four feet away, so something else was clearly going on.

But Bell's experiments   had proved a further critical point in the case,   hinging on the different size of shotgun   the two men had each been carrying.

The fatal shot had been fired by a large shotgun, something rather like this, something of 12 bore.

Now, the victim was not armed with a shotgun of this bore.

In fact, his tutor was.

The obvious implication was that, in fact, he'd been murdered.

Joseph Bell, the model for Sherlock,   had now himself followed in the great detective's footsteps   and further established the credibility   of ballistics evidence.

Sherlock was the first to showcase   other important aspects of ballistic science,   not least the groundbreaking area of bullet trajectory   in a case that involved a murder suicide shooting.

But there were still four cartridges in the revolver.

Two had been fired and two wounds inflicted so that each bullet could be accounted for.

(Holmes)   So it would seem.

Perhaps you'd account also for the bullet that struck the window.

By George.

However did you see that?

I looked for it.

(gun expert)   Not only does Holmes spot this bullet hole, by examination of this hole he's able to determine which direction the bullet has passed.

With a gunshot, the exit is larger than the entrance.

The entrance of that little tunnel created by the bullet will be about caliber size, about the size of the bullet... ..and the exit will be larger, it will splinter, it will create spalls of wood.

(Lestrade) &nbspThen a third shot has been fired and therefore a third person has been present.

But who could that have been?

And how could he have got away?

That is the problem which we are now about to solve.

(gun expert)   Like a good forensic scientist, Holmes immediately seeks to confirm his hypothesis and look for a piece of evidence that he already knows is there.

(door creaks shut) The servants say they found the window open.

There might have been a third person in the affair who stood outside the opening and fired through it.

I'll see what fresh evidence out here has to offer.

And he finds virtually right away the ejected case from the weapon that belonged to this third party.

I really think, Inspector Lestrade, that our case is almost complete.

(gun expert) &nbspThis advanced thinking about where bullets are coming from, where they're going and what they're passing through in between, it comes before an awful lot of real-world crime scenes that would exist later, where trajectory was vitally important.

Holmes is really ahead of the game in terms of the forensic reality.

TV and movie adaptations of Sherlock fueled his popularity,   and the great detective   is still a massive box office draw.

Almost as soon as cinema began,   the first film appeared in 1906.

The name's Sherlock Holmes and the address is 221B Baker Street.

But there is one current portrayal of Holmes   that scores big points with the real forensic detectives.

(man)   I'm not a huge fan of most serialized crime dramas, because they are so unrealistic or they are so out of the realm of possibility that they just become uninteresting to me.

However, the series  Sherlock, with Benedict Cumberbatch and Martin Freeman, is probably one of the most enjoyable series I've ever watched.

To me, it's really about the scientific detection of crime, careful analysis of fact, focus on minutiae to create the larger picture and... taking the audience on that journey with Holmes as he makes those discoveries.

Freak's here.

Bringing him in.

(woman)   He's not hard on the eyes.

(laughs) And, yeah, certainly the fact that he's good looking makes it very appealing to the female cohort, but I think also, there's something about the brilliance of Sherlock that's very attractive as well.

The latest version of Sherlock really captures his befuddlement that people just, why don't people get it?

You know, clearly, it's so obvious that this is the answer.

What's wrong with everyone?

And why does everyone think that he's strange?

- It's obvious, isn't it?

- It's not obvious to me.

Dear God, what is it like in your funny little brains?

It must be so boring.

We actually get to watch him making his deductions, and they point it out to you on the screen as it's happening and you realize, yep, that's there, that's there.

It's very invigorating.

It accomplishes the same thing that Conan Doyle accomplished, which is to make you feel like, one, this kind of deduction is possible, two, that you could do it yourself if you paid close enough attention, and that's what draws you in.

Sherlock's fast-paced deductions   intrigue and fascinate.

Her coat is slightly damp.

She's been in heavy rain.

No rain anywhere in London in that time.

Under her coat collar is damp.

She's turned it up against the wind.

Cumberbatch's character, Sherlock, he has moments where there are revelations coming to him.

She's got an umbrella in her left-hand pocket, but it's dry.

Strong wind, too strong to use her umbrella.

We know from her suitcase that she was intending to stay.

She can't have traveled more than two or three hours as her coat hasn't dried.

He makes immediate connections between minute details that cause him to arrive at incredibly profound conclusions that can alter the case.

So where has there been heavy rain and strong wind within the radius of that travel time?

- Cardiff.

- It's fantastic.

Do you know you do that out loud?

For me, it's not quite like that.

You try to take in as much as you can, you demand silence around you, you demand that you get time to reflect and carefully analyze the details of the crime.

The reality is you don't know what's important at the time.

You don't know what's gonna be important until later on, you get a second piece of information that makes the old stuff that you learn become newly important.

So for me, it takes quite a bit longer and it requires a lot more silence.

(laughs)   For centuries,   poisoning had been a popular method of murder.

It was difficult to trace... and then along came Sherlock.

He was at the frontier of toxicology,   the science of poisons.

At the time of Sherlock Holmes, forensic toxicology was just only really a dream.

People looked upon Sherlock Holmes as kind of the guide to identifying poisons and identifying substances.

Ah!

You've come at a crisis, Watson.

If this paper remains blue, all is well.

If not... it means a man's life.

When Sherlock Holmes first arrived on the scene, the use of laboratory testing had really only just begun and, because of the fact that we had advances in technology, poisonous substances, substances that were around in Sherlock Holmes' time that were invisible to us, were now visible.

Robert Curley was 32,   newly married and living in Wilkes-Barre, Pennsylvania.

Over 11 months, he developed strange symptoms.

Over time, he began to become sick.

He developed signs and symptoms which were thought to be due to something called Guillan-Barré syndrome.

And he slowly got sicker and sicker.

Eventually, he was hospitalized and then he died rather suddenly in the hospital one day.

Standard post mortem tests produced a shocking result.

There were high levels of a deadly pest control poison,   thallium, in his body.

The question was... how did it get there?

It was thought that he might have been exposed at the workplace where he was working.

They were rewiring a chemistry lab in a university and it just so happened that, in that chemistry lab, there was a sign, a little note, handwritten note, saying "Warning: thallium.

Don't touch me or you die."

So could this have been an occupational exposure case where the man had been unintentionally exposed to thallium?

But how about all his other co-workers?

Robert Curley's co-workers were all tested   for exposure to thallium.

(news)   An attorney for Morgan Electrics says he's delighted that eight employee test results are in and none showed signs of thallium poisoning.

With workplace exposure discounted,   Robert Curley's work possessions were examined.

Traces of the deadly thallium were found in   the flask he used for iced tea.

It was determined that the iced tea he had had a lot of thallium in it and so it was thought that someone must have put thallium in his iced tea and that's what caused him to be sick.

Then there was a suspicion that one of his co-workers had played a trick on him.

They were known to play tricks on each other and it was thought that maybe this was a practical joke that had gone horribly wrong.

Could this have been one of his friends putting something in his iced tea?

Despite close questioning   of Robert Curley's co-workers, investigators found no evidence   that any of them were involved in the death.

(Michael) &nbspSo then the plot thickens.

The strange thing was that he didn't die suddenly of thallium, he was sick over time, so he had to have been exposed on several occasions.

Not just once, but several occasions.

To help piece together this puzzle,   one of America's top forensic scientists was brought in,   none other than Michael Rieders' father,   Dr. Frederic Rieders.

My father was a world-renowned forensic toxicologist and he also enjoyed the Sherlock Holmes stories.

Sherlock Holmes is a person that we all looked up to, a person who we felt was emblematic of what one should be as a forensic scientist.

The Robert Curley case was very much a case that could be a perfect Sherlock Holmes adventure.

My father was the one who came up with the plan to do the testing and it was his approach to this case that really broke the case open.

Dr. Frederic Rieders' Sherlockian approach   involved following the evidence trail   all the way back to Robert Curley himself.

(news)   Investigators remove Robert Curley's body from Mount Olivet cemetery in the back mountain.

(Michael)   Sherlock has taught us that the evidence can speak, that each little piece of evidence can tell a story if we examine it carefully.

In the case of Robert Curley, since his body hadn't been cremated, his body could be exhumed and his body could tell us the story of what happened.

But the evidence trail led down a surprising route.

Now, when you're poisoned over a period of months, poison goes into your body and then it goes out of your body and it does its damage on the way.

The only place that it leaves a trace, a record, is in your hair.

And as your hair grows out, it creates a record day by day of your exposure to drugs, chemicals, poisons.

In the case of Robert Curley, his hair still remained on the back of his head.

Michael Rieders himself   was involved in examining the hair samples   and unraveling Robert Curley's history of thallium poisoning.

It really got me into the mind of Sherlock Holmes.

It got me really to understand how Sherlock Holmes was so much like modern-day forensic scientists, wanting to understand how to solve the case, but doing it through the process of experimentation and the process of gathering facts.

There was enough hair that it could be laid out and examined section by section, which represented week by week his exposure to thallium over a period of many, many months.

When he was given a large dose, there'd be a large peak and that really showed the timeline of poisoning and showed that it had to be multiple poisoning events which terminated in a massive single dose of thallium poisoning in the hospital.

And the story changes into who would have had access to Robert Curley over the many, many months that he was made sick?

(news)   The arrest and arraignment of 33-year-old Joann Curley answers a five-year-old open question.

Will authorities ever charge anyone for the murder of Wilkes-Barre electrician Robert Curley, Joann Curley's husband?

And after all other people were eliminated, the only person who had access to him during every one of those times was his wife, Joann Curley, and she also was there in the hospital when he was given that fatal dose.

So what we had was evidence from his body telling us that he had been serially poisoned with thallium and then given a massive overdose in the hospital.

As Sherlock Holmes tells you, if you've ruled out all other possibilities, the only one remaining, however unlikely, however incredible, is the one that remains.

And the only one that remained was Joann Curley, his wife.

(news)   The clanking of leg shackles on Joann Curley echoes throughout this hallway in the Luzerne County Courthouse.

Just moments earlier, Curley confessed a six-year-old secret.

She repeatedly poisoned her husband Robert back in 1991.

The apparent motive, nearly $300,000 in insurance money.

She confessed ultimately after seeing the evidence, after her... with her own eyes, seeing the forensic evidence of when he was poisoned, that his hair showed he was poisoned on several occasions and then the fatal poisoning in the hospital, she confessed to what she did.

Sherlock Holmes was very much our guiding star and Sherlock Holmes teaches us a very valuable lesson in forensic science, and that is don't develop your final theory till you have all the facts, until all the facts are in.

For his millions of readers,   Sherlock pretty much wrote the book,   albeit fictional, on forensic investigations.

But right from the very start,   the great detective's quantum leaps   didn't go unnoticed in the professional community.

Sherlock Holmes was writing about all of this stuff in fiction, when people were only beginning to think could this be used in practice?

The first person to turn   the great detective's fiction into fact   was a contemporary and fan of Sherlock,   Austrian judge Hans Gross.

He would be constantly confronted with how little or how incompetent or how inept the criminal investigations that had been presented to him were.

And he saw this over and over again in his courtroom.

Investigators bringing in suspects where they had beaten confessions out of them, instead of following evidence, instead of understanding what the complete picture of the evidence said.

He thought, "Well, since they don't know how to do it and it's so obvious to me what needs to get done, I'm just gonna have to write a manual for them."

He called it a Manual for Criminal Investigators.

Published in 1893,   six years after the first Sherlock adventure,   Gross's book remains the most important ever written   about crime scene investigations.

It's a very thorough, comprehensive manual for criminal investigators on how they should approach evidence and investigate their cases.

(Hans Gross)   The scene of the crime must be inspected both in its general aspect and in detail and must be considered in relation to the facts.

The time allotted to a close examination is far from being lost.

Gross, like Sherlock,   realized that at a crime scene   anything and everything may be of value.

He also stressed the importance   of an investigator's professionalism.

He talks about the fact that, to be a modern investigator, they have to use modern techniques, modern thinking, they have to use science.

He makes it very clear that's the kind of investigator who should be investigating crime, which is, not a mistake, very similar to the Sherlock Holmes character.

Not just Sherlock Holmes' techniques,   but even the great detective's personality   had been taken from the pages of his adventures   and turned into an instruction manual.

(Carolyn)   Undoubtedly he was influencing Gross and the development of how one should go about preserving a scene, gathering evidence and later examining it, what could be found out.

Undoubtedly, Holmes was in there.

It's synergy.

There's a synergy going on between the professional forensic community and popular fiction through Sherlock Holmes.

Not only do we have a fiction author who has created this perfect vehicle for expressing these ideas, but he's written stories that everyone enjoys.

We have Hans Gross, who's now saying, "I wanna write it for investigators."

They're ready for this because we have this character.

So in that way, Conan Doyle, through Sherlock Holmes, made forensic science, I think, possible.

Sherlock Holmes had the first ever forensic crime lab.

23 years later, in 1910, the first real lab was created   by another avid reader of Conan Doyle's stories.

Edmond Locard, spurred by Sherlock's teachings,   would go on to make the most important single contribution   to forensic science.

Edmond Locard is one of the biggest fans of Sherlock Holmes that ever existed.

He's inspired by this notion that you can use science to understand what happened at a crime scene and who's responsible for it.

His idea is he's gonna start his own crime lab.

He assumes that's happening all over the world.

He assumes this because of what he's read in the Sherlock Holmes works and he finds nobody's using them.

There's no fingerprinting units, no scientific trace evidence examination, there's no forensic chemistry, it's not happening anywhere.

In frustration and almost in despair, he comes back and says to the local police department in Lyon, "I want to start a forensic lab."

They say, "Fine, but we don't have any real space for you and we don't have really a budget, so you're gonna kind of have to use what we can give you."

They give him this attic space that is utterly inadequate for what he's trying to do.

But that becomes the very first police crime lab in history and it started with Sherlock Holmes.

(Edmond Locard) &nbspI heard that a police expert would not find it a waste of time to read Doyle's novels for, in the adventures of Sherlock Holmes, the detective is repeatedly asked to diagnose the origin of a speck of mud, which is nothing but moist dust.

The presence of a spot on a shoe or a pair of trousers immediately made known to Holmes the particular quarter of London from which the visitor had come.

Ah, Watson.

Observation tells me you've been to the Wigmore Street Post Office this morning.

Right.

But I confess, I do not see how you arrived at it.

I mentioned it to no one.

It is simplicity itself.

Observation tells me that you have a little red mold adhering to your instep.

Just outside the Seamore Street office, they have thrown up some earth which lies in such a way that it is difficult to avoid treading in it in entering.

The earth is of that particular reddish hue that is found, as far as I'm aware, nowhere else in the neighborhood.

It's so absurdly simple that an explanation seems superfluous.

Sherlock understood the value of such trace evidence   and kept collections of samples of every kind.

Locard also kept meticulous soil, mineral,   fiber and hair samples.

(Brent) &nbspClassifying trace evidence comes from the Sherlock Holmes series, but is made real by probably one of the best known forensic scientists in history, and he's inspired directly by Sherlock Holmes.

He admits this freely and openly.

This is not a remote connection, this is a direct connection between Sherlock Holmes and forensic science and classification techniques.

The use of the microscope to identify   minute pieces of evidence   is first seen in the Sherlock Holmes stories.

Nowadays, small little fibers have so many different textures and shapes, they could break a case wide open.

And it was something   Holmes was openly keen for the police to take up.

But it was Edmond Locard   who best followed Sherlock's example.

Locard started working on cases and actually going out to the crime scene and, like Sherlock Holmes, assessing the scene, processing the scene, bringing back the evidence.

It was one of Locard's most celebrated cases   that gave rise to his greatest contribution to forensics...   A quintessentially Sherlockian way   of looking at trace evidence.

In 1912, late into a warm summer night in Lyon, France,   bank clerk Emile Gourbin and several friends   enjoy wine, cigars and a card game.

(laughs)   Several miles away, Marie Latelle,   a fashionable young woman   and Emile's sometime girlfriend,   was in her home.

It was approaching half past midnight   when an intruder entered Marie's apartment.

(gasps)   (chokes)   When Marie's body was discovered the next morning,   a doctor estimated the time of death   to have been half past midnight.

The question was, who had so cruelly ended Marie's life?

Suspicion fell on Marie's on/off boyfriend Emile.

As Emile's friends readily confirmed to the police,   they were all playing cards together at 12:30 that night.

Emile had a airtight alibi and he said, "No, I have a whole group of people who are willing to testify that I was with them playing cards at the time."

With the police investigation seemingly at a dead end,   they brought Edmond Locard onto the case.

Edmond Locard was doing in real life what people were reading about in the books.

Locard was looking for traces.

What could our perpetrator have walked away with?

(Locard)   It is impossible for a criminal to act, considering the intensity of a crime, without leaving a trace.

He wanted to inspect Emile and see if he could find anything on him.

He had quite dirty fingernails.

Locard took some scrapings from underneath the fingernails.

Such innovative gathering of trace evidence   was straight out of "Sherlock Holmes."

Locard was doing it for the first time in real life.

Locard examined the debris in microscopic detail...   ..not satisfied until he could account   for everything he found there.

A pinkish dust within the residue stood out.

On further examination,   Locard realized the particles were from a cosmetic powder.

This minute trace evidence   was vital to solving the murder of Marie Latelle.

As the killer grasped Marie's neck,   his nails scratched off microscopic amounts   of her cosmetic powder...   ..indelibly linking the murderer to the crime.

Locard then carefully examined Marie's face powder.

He discovered it directly matched   the powder found underneath Emile's nails.

Faced with this unprecedented evidence,   Emile Gourbin confessed.

At 12:30, he entered Marie's apartment...   ..and strangled her to death...   ..never imagining he would carry away   vital evidence on his hands.

To cover his tracks, arriving just before his friends,   he put the clock back by an hour.

His friends then unknowingly   gave the police Emile's perfectly constructed alibi.

But for Locard's pioneering use of Sherlockian trace evidence,   Emile Gourbin would have escaped justice.

It was from this case   that Locard formulated his exchange principle.

Whenever two things come into contact,   they leave a trace on each other.

It's that idea of exchange, so if I come into contact with a table, I'm leaving traces, I'm leaving fingerprints, I'm leaving DNA.

But at the same time, I'm taking dust from the table or maybe a paint chip from the table, so I'm leaving a trace on the table, but the table's also leaving a trace on me.

(Locard)   There is no such thing as a clean contact between two objects.

The two bodies come into contact, mutually contaminating each other with minute fragments of material.

The microscopic debris that covers our clothing and bodies are the mute witness, sure and faithful of all our movements and all our encounters.

That is something right out of a Sherlock Holmes novel, that whenever two things come into contact, they leave a trace.

And, as forensic scientists, we play that out on every crime scene that we come across.

We rely on Locard, just like Locard relied on Holmes.

Locard's principle of exchange is the first tenet in crime scene investigations and forensic science.

End of file.

Until the discovery of DNA,   fingerprints were the most individual trace evidence   a criminal could leave behind them.

Sherlock Holmes was a remarkably early adopter   of fingerprint evidence.

Their routine use in criminal investigations   was decades away.

Now, look what we found after your visit last night.

You are aware no two thumb marks are alike?

I have heard something of the kind.

Well, then.

Would you please compare that print with this wax impression of young McFarlane's right thumb, taken by my orders this very morning?

Now, that is final.

Yes, that is final.

It is final.

Even with his magnifying glass,   Sherlock could never have seen invisible blood evidence.

In one of investigator Karen Smith's cases,   a vital piece of evidence was left behind,   but it was virtually undetectable.

(Karen)   When I got there, everything was in disarray.

Chairs were overturned.

There were beer cans, trash... and it was very obvious that we had quite an extensive scene to deal with.

So the first thing that we did is we obviously documented it with photography.

That's crime scene 101.

And, as we moved in... ..we saw a shoe print in blood, or what appeared to be blood, on the linoleum floor in the kitchen and it was a zigzag pattern.

So now we start investigating the shoe print on the linoleum and we used an enhancement tool called Amido Black, which is a protein dye.

As well as enhancing the shoe print,   the Amido Black dye began to reveal something unexpected.

And as we were using that to enhance the shoe print, some of it spilled over to the next area.

It was about to make the invisible visible,   a crucial piece of evidence   incontrovertibly linking a suspect to the scene.

Which was fascinating, because we hadn't even seen it with our naked eye.

It was latent, it was invisible until this dye hit it and then it burst onto the scene.

It revealed a bare toe print.

When we turned them in and they did the comparison with a possible suspect's toe print, that was a big break in the case.

His toe prints in his own blood obviously placed him at the time of the crime in the crime scene and this was a big lesson.

It's not always what you think it's going to be, and Sherlock was the mastermind of that kind of thing, things that are not always as they seem.

It is final.

And, back in Sherlock's adventures,   the fingerprint Inspector Lestrade has discovered   turns out to be something quite different,   much to Sherlock's amusement.

Oh, dear me, dear me.

The thumb print had not been there the day before.

I pay a good deal of attention to matters of detail.

Therefore, it had been put on during the night.

- But how?

- Well, very simply.

Jonas Oldacre made a wax impression of McFarlane's thumb from a document seal, realizing what absolutely damning evidence he could bring against McFarlane using that mark.

It was the simplest thing for him to moisten it in blood from a pinprick and then to put the mark upon the wall during the night.

This idea of fraudulent fingerprints   in the Holmes adventures   captured once more the imagination   of the great trace evidence pioneer Edmond Locard.

Using tree gum,   Locard made an impression of the ridges of his own thumb.

Then, making a batch of his own true fingerprints,   Locard challenged himself to spot the fake among them.

To find the fraud,   Locard had to look not at the ridges and lines,   but at the microscopic skin pores on them.

The pores' minute sizes and intricate patterns   make them infinitely harder to counterfeit.

Locard didn't just spot the fake.

In doing so, he pioneered the forensic science of poroscopy.

Now, if a print isn't good enough to use,   the pores within it might prove an identity conclusively,   all thanks to Sherlock.

But some crime scene prints are so smeared,   there's no detail left in them to examine,   in which case all a detective's Sherlockian skills   are called for.

Upon entering one murder scene,   Dr. Henry Lee found a piece of evidence   from which he was able to make deductions   that proved pivotal in solving the case.

On a wall, we found a big hand print.

It's a bloody hand print.

Usually, when we look to a fingerprint or a palm print, we need ridges.

But this has none, just a bloody contact print.

So I tell the detective, "Cut this wallpaper, take it back."

He said, "Dr. Lee, it has no value, no comparison value, because no ridges."

I thought about Sherlock Holmes, too.

Use Sherlock Holmes' logic, this hand big hand.

So that tells me... he either play football or basketball, or maybe both.

Of course, a week later, the detective come back, tell me, "Dr. Lee, here I have a good suspect called Rosberg."

I said, "Why don't we check him, the background?"

Turned out he's the basketball team captain, play basketball and football with that big hand.

The detective thanked me.

I tell him to read   Sherlock Holmes   and I say, "I learn from Sherlock Holmes."

(Holmes)   There is no branch of detective science so important nor so neglected as that art of tracing footsteps.

Happily for me, much practice has made it second nature.

Perhaps never a truer word   was spoken by the great detective,   for evidence relating to footprints and shoe marks   lagged far behind the other forensic sciences,   right up until the end of the 20th century.

Holmes was almost 100 years ahead in his thinking.

A bit like the relationship between science and science fiction, it did stimulate a lot of us to think about what might be possible.

He was more than six feet high.

He was in the prime of life.

He had small feet for his height.

He wore coarse, square-toed boots.

Sherlock was a huge advocate of shoe mark evidence.

He could tell a person's stride length or how much they weighed based on if it was a deep print or was it a shallow print?

All of these crazy things, he could come up with just based on simple shoe wear tread patterns.

The height of a man, nine times out of ten, can be told by the length of his stride, a simple enough calculation.

It was child's play.

He was able to deduce a great deal from that and I think he would challenge most forensic scientists to get close to the detail that he claimed he was able to get.

Some of the work he did nowadays we know to be blatantly wrong.

I mean, he had various postulations about calculating height from people's stride length and, really, he shouldn't have been doing that.

We know it can't be done.

He was a pioneer in the field, he was entitled to get things wrong.

That's how knowledge progresses.

He wasn't making any mistakes that podiatrists weren't making years later themselves.

Sherlock's obsession with shoe print evidence   inspired the most recent forensic advance:   gait analysis, literally reading human locomotion.

Ah!

Now, you know my method.

It was founded upon the observation of trifles.

(Wesley)   He was looking at footprints people had left at crime scenes in order to produce a conclusion as to what type of gait the person had.

The impression of the left foot is always more than that of the right.

He put less weight upon it.

Why?

Because he limped.

He was lame.

(Wesley)   That was years ahead of its time.

This Holmesian technique   is now applied to closed circuit TV,   matching a suspect's gait,   their individual way of walking,   to surveillance footage of a crime scene.

(Wesley)   Forensic gait analysis was only used for the first time in 2001, so Sherlock Holmes was 120 years ahead of practice.

All of Professor Vernon's own Sherlockian skills   were needed in a murder case on the English coast.

A suspect, Gary Chester-Nash, is arrested.

He has blood from the scene on his shoes.

And what he said was he'd been living in a squat with another person.

The other person was of foreign extraction and had a very complicated name that he couldn't remember and that particular morning, this foreign gentleman got up, borrowed all Chester-Nash's clothes, including his shoes, disappeared for an hour and a half, returned, gave him his clothes and shoes back and left.

And the suggestion he was making was that it was this person that had murdered the woman and not himself, and that was how the blood had got onto his shoes.

Professor Vernon was asked to examine the shoes   and see whether he could confirm   that two different people had worn them.

A similar approach to those that Sherlock Holmes would have adopted many years ago.

Changed the laces three, no, four times.

There are traces of flaky skin where his fingers have come into contact with them.

(Wesley) &nbspIf he could be around now, I imagine he would have done exactly the same.

I'd looked at the foot impression on the insole of that shoe... ..and the toe impression.

After meticulous analysis,   Dr. Vernon found only a single foot impression in the shoe.

(Wesley)   The shoes had just had one wearer, not the two wearers, as claimed.

But there was no alibi.

He'd been the only person to have worn the shoes and he then had to admit to having been at the crime scene.

With the help of Professor Vernon's evidence,   Gary Chester-Nash was jailed for life.

Crucial to making deductions are knowledge and experience,   but no investigator has as vast a database of either   as Sherlock Holmes.

He called it his brain attic.

Its importance is highlighted   by one of Dr. Henry Lee's most tragic cases.

A family was stabbed to death in a triple murder   at their home in Derby, Connecticut.

The scene is soaked with water, all over the place.

Tried to get rid of the evidence.

Because the scene flooded with water... therefore it's almost impossible to find any shoewear pattern.

It's all washed... except in the master bedroom, Nina's body was found next to a bed.

Under her body, that's the only area the carpet is dry.

We see some bloodstain.

We enhance the area, when colorless become blue color.

We found a bloody... shoe print.

We took back to the laboratory, used image computer enhancement procedure...

The sneaker print showed up.

Dr. Lee compared the indistinct shoe print   with a vast database of tread patterns.

Sherlock Holmes had all his databases in his head and all the information he might need, but we now have the ability, through computer searching, to make comparisons and potentially identify an offender and that is something that Sherlock could only dream of.

The search revealed a match...   for the sneaker print.

This proved critical when the same shoes were found in a bag   near the crime scene.

It was a vital piece in the puzzle   that brought the murderer to justice.

Sherlock Holmes taught us to look at each piece of physical evidence, try to put the puzzle together so we can find the suspect, so we can speak for the victim.

All because Sherlock Holmes.

He really changed the whole world of criminal investigation.

As Sherlock's fame grew, Arthur Conan Doyle,   by now himself a public figure,   frequently received letters appealing for help with crimes.

One such letter would lead Doyle   to turn Sherlockian detective himself.

It would also see him spearheading   one of the most important changes   to the British justice system   since the arrival of Sherlock himself.

In 1903, in an English Staffordshire village,   a series of horrific night time animal mutilations   terrified the local population.

Somebody was cutting the animals in long deep slits, so that they would bleed to death slowly, and there was a real concern over who was doing this and how it was occurring, but no real obvious suspects emerged until someone started writing letters implicating a local solicitor named George Edalji.

George Edalji lived in the local vicarage   with his father, the village priest.

(Brent)   This crime occurs in a very small country community and the Edalji family sticks out as an anomaly because they are, after all, foreigners.

After more gruesome mutilations,   the police arrest George Edalji   and confiscate evidence from the vicarage.

The police gathered up a coat that they said had hairs from the ponies on it, there was Edalji's razors, the weapon that was used to cut the ponies.

At trial, Edalji is found guilty of the mutilations.

He is sentenced to seven years' hard labor.

But after a public outcry at his controversial conviction,   three years into his sentence George Edalji is released.

(Brent)   Because of the popular sentiment, he was actually let out.

But he wasn't exonerated.

He was still... thought to be responsible for the crime and police weren't really looking at any other suspects.

It was at this time that Edalji wrote a letter.

(Carolyn)   Quite a lot of people wrote to Sherlock Holmes to try and solve crimes and to solve problems that they were having.

Edalji's letter came to Conan Doyle when he was grieving for the death of his first wife and was struggling to get interested in really doing anything.

Hard to know why it stood out from all the rest, but he did start to investigate.

Doyle always felt a little bit overshadowed by Sherlock Holmes.

I think, nonetheless, there was a vanity to him that said, "I won't write him anymore, but I can perhaps be him."

Conan Doyle visits the crime scene   and begins to investigate.

(Brent)   Conan Doyle's looking at physical evidence, he's considering whether or not the police did a good job.

He finds himself in the same position that Sherlock Holmes has always been in, which is the investigation isn't done, it's terribly biased and racist and the physical evidence has been all but ignored by police investigation.

Knowing Sherlock's mind better than anyone else,   Conan Doyle examines the police evidence   used to convict Edalji.

The hairs found on Edalji's clothing matched the sample of pony hair from the underside of the belly.

Conan Doyle pointed out that, had someone been with the pony, leaning up against it, cutting its belly, you'd expect some from the mane, some from the neck, some from other parts.

And actually, all the 29 hairs found were very similar to the ones just from that underbelly part, like the sample the police had acquired for comparison.

Edalji's razors, there was debate over whether there were hairs on them.

There didn't seem to be any hairs at the house, Edalji's house, when it was gathered, but allegedly there were horse hairs on them later.

That seemed very odd.

The physical evidence, as he was looking at it, didn't line up to the crime at all.

Conan Doyle felt, "I need to know if he actually did it."

"One of the ways I can do this is I can meet him and I can talk with him and I could figure out who this man is as a person."

Holmes, of course, famously said that, you know, you only need to look at a man's shoes, his cuffs, his collar and such and it would tell you pretty much everything you needed to know.

This is something you get in the novels.

Well, the first time he met Edalji, it's interesting that it was Conan Doyle's expertise as an eye doctor that came to the fore, because again he stood back and observed before going straight in to talk and he noticed how close Edalji was holding the newspaper to his eyes.

Edalji has the newspaper up to his face, he's looking at it sideways trying to read it, trying to read it at very close range, because his eyesight is so poor he's not capable of reading it just looking at it front on.

So when Conan Doyle sees this, he realizes this is somebody who is physically incapable of going out into a field at night, stalking animals, cutting their throats and then getting away in the dark.

And that to him was proof positive that this man was innocent of the crime.

Conan Doyle begins to campaign for a retrial   to exonerate Edalji.

He writes about it in the newspapers.

As a public figure, he lobbies politicians and the police.

For the police, you see, Doyle was the author of   Sherlock Holmes, a man who had created this great crime fighting figure.

They would, I think, have liked to have had him on their side, but it became apparent very quickly that that wasn't going to be the case.

In fact, there was a lot of fractiousness.

And that's one of the things that really makes him a lot like his character Sherlock Holmes in real life, and that is that he is not afraid to speak the truth about law enforcement.

You're getting it wrong.

You're doing it wrong.

You're incarcerating people wrongfully and the evidence proves that this is the case and you haven't looked at it.

Doyle's campaign led to a retrial.

Edalji was exonerated for the horse mutilations.

But despite the fact that Conan Doyle was able to help prove the innocence of George Edalji for these mutilations, the police still wouldn't let it go.

They refused to believe that Edalji was actually innocent.

This experience fueled Doyle's passion   to put right miscarriages of justice.

He became a campaigning and influential voice   in the setting up of the first official   British Court of Appeal two years later.

So because of this character that he created, he now has this tremendous opportunity to have an impact and influence on real-life cases and that's one of the most exciting things about the Holmes series, is that it not only has inspired generations of forensic scientists, but it also changed the life of the author to make him more of an advocate for the forensic sciences and for competent, adequate criminal investigation and scientific investigation.

Sherlock Holmes, the first CSI,   continues to inspire detectives.

On TV and at the movies, he is as popular as ever,   but his lasting legacy is that, even today,   he continues to help solve crimes.

We keep talking about Holmes like he was a real person and not just a figment of Doyle's imagination, but Sherlock still has impact on the real world today.

He always will.

There was very little Sherlock Holmes.

There are 56 short stories, there are four novellas, so Doyle did what every writer should do.

He quit while he was ahead and left us wanting more.

I think that wanting more has lasted all the way down the generations.

Conan Doyle's main achievement would be to have created a character that led the way to how crime could be solved better.

The world is changing, but Sherlock Holmes' theory, Sherlock Holmes' approach will never change.

Sherlock's legacy is his delight at discovering the truth.

The new series has rekindled that passion and has put it in terms that the next generation can really understand.

I wish Holmes was around now.

He could probably show us a thing or two.

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please visit PBS.org.

How Sherlock Changed The World &nbspis available on DVD.

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