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  • Crime.

  • You know that thing that was almost solved

  • -by a flasher dog in 1980's.

  • But specifically this story is about

  • how we increasingly solve crimes using forensic evidence.

  • It's that thing that is just a staple of TV crime shows.

  • Pull it from the torso on the left.

  • Pull it from the boat on the right.

  • Two hearts beat as one.

  • Matches up perfectly.

  • That's a match.

  • We've got a match.

  • And it just found us a match.

  • Visible match.

  • -We've a match. -Match.

  • Were you able to determine

  • which monkey bit him?

  • The bite marks match those of the monkey found at the scene.

  • Wow!

  • That last one was presumably

  • from one of the crossover episodes where the team from Law & Order,

  • worked a case with the cast of Monkey Law and Monkey Order.

  • -But...

  • on TV and in real life forensic science plays

  • an important role in criminal convictions.

  • Prosecutors often complain about a so called C.S.I. effect,

  • where jurors expect to see forensic evidence in every case.

  • The problem is, not all forensic science

  • is as reliable as we've become accustomed to believe.

  • A report in 2009,by the National Academy of Sciences

  • found that many forensic scientists

  • do not meet the fundamental requirements of science.

  • And a report last year by a Presidential Science Council agreed saying that,

  • "expert witnesses have often overstated

  • the value of their evidence, going far beyond

  • what the relevant science can justify,"

  • and that's the thing here.

  • It's not that all forensic science is bad,

  • 'cause it's not, but too often,

  • it's reliability is dangerously overstated

  • and one sign of that is that forensic experts in court

  • are often nudged to use one very convincing phrase.

  • To a reasonable degree of the scientific certainty...

  • To a reasonable degree of scientific certainty...

  • To a reasonable degree of the scientific certainty...

  • Within reasonable scientific certainty...

  • To a reasonable degree of scientific certainty...

  • Are you able to say that within a reasonable degree

  • -of the scientific certainty? -Yes.

  • And here's the thing that phrase

  • does have a persuasive ring to it. Unfortunately,

  • as that Presidential Council pointed out,

  • it has no generally accepted meaning in science.

  • It's one of those terms like, basic or trill

  • that has no commonly understood definition.

  • Am I trill?

  • Is that good or bad?

  • I mean I do feel trill, so I'm guessing it's awful.

  • And-- when bad science

  • is confidently presented, terrible convictions can happen.

  • In fact, among the hundreds of people

  • who have been exonerated by DNA testing since 1989,

  • in nearly half of their cases,

  • there was some misapplication of forensic science

  • and there are people behind those numbers.

  • Take Santae Tribble, who was convicted of murder

  • and served 26 years. In large part,

  • thanks to an FBI analyst who testified that his hair

  • matched hairs found at the scene.

  • And as he will tell you,

  • the evidence was presented, as being rock solid.

  • They said they matched my hair

  • in all microscopical characteristics.

  • And that's the way they presented it to the jury

  • and the jury took it for granted that, that was my hair.

  • But you know, I can see, why they did.

  • Because who other than an FBI expert

  • would possibly know that much about hair?

  • Except of course,

  • whoever stalled Amanda Seyfried at the 2009 Oscars.

  • Breath taking waves,

  • without loosing any of their body or bounce.

  • -Stunning.

  • -Stunning!

  • -Stunning.

  • -Stunning.

  • Stunning! Stunning! Stunning! Stunning! Stunning! Stunning!

  • The jurors in Tribble's case, were actually told

  • there was one chance in ten million

  • that it could be someone else's hair, and guess what?

  • He was exonerated.

  • Because once DNA analysis became available, his lawyer tested

  • the thirteen hairs from the case

  • and not only were none of them his,

  • some of what they found was incredible.

  • Nine of the hairs had come from the same source,

  • a couple had come from different sources

  • and one was a dog.

  • Two different FBI agents who had, eh,

  • looked at that and analyzed it, didn't recognize that it was dog hair?

  • It was a K9.

  • It was a domestic dog, yes.

  • My personal conclusion was,

  • -the dog committed the crime.

  • Okay.

  • So, first, it is amazing that he is able to laugh at that,

  • but second, if a dog did commit the crime

  • there's really no recourse there because there is actually no law

  • against dogs committing murder

  • and that's a fact that learned in Air Bud 9,

  • Fuck the Paw-lice!

  • And it turns out,

  • Tribble is not the only case where FBI experts

  • overstated their confidence in their results.

  • The Innocence Project

  • and the National Association of Criminal Defense lawyers

  • found from the 1970's through 1999,

  • in 268 cases where FBI hair analysis led to a conviction,

  • 257 or 96 percent of them had errors in analysis.

  • Oh, it gets worse

  • because nine of those defendants had already been executed,

  • which is horrifying.

  • And you would expect FBI hair analysis

  • to have a high rate of accuracy than your friend's hair analysis

  • of you can totally pull off bangs,

  • because you can't,

  • you absolutely can't, believe me I couldn't,

  • just learn--

  • -learn from our mistakes kids.

  • Save yourselves!

  • It's too late for me.

  • And look,

  • it's by no means,

  • just microscopic hair comparison which has had

  • the reliability of these results overstated.

  • Those reports that I showed earlier suggests

  • there is weak scientific support

  • for some aspects of techniques like

  • a blood pattern, footwear, firearm and bite mark analysis.

  • And you must be familiar with that last one from

  • cool scenes like this:

  • A little 3D magic for clarity and I give you

  • the killer's incisors.

  • (COMPUTER BEEPING)

  • Oh, Yo!

  • The computer rated it "Yellow rectangle."

  • And we all know yellow rectangle is the highest level of match

  • a computer can give you about teeth.

  • (AUDIENCE LAUGHING)

  • Look, in the real world, bite mark analysis

  • is highly subjective and unreliable.

  • The President's Council found the entire discipline,

  • does not meet the scientific standards

  • for foundational validity.

  • Which I believe, is science speak for "Bullshit!"

  • But people have been sent to prison

  • on the basis of bite mark testimony by experts like,

  • Dr. Michael West.

  • The science of bite marks analysis, is very accurate.

  • NARRATOR 1: When it comes to bite marks,

  • West consider himself "The maestro."

  • He's found bite marks on a decomposed body

  • submerged in a swamp,

  • on a corpse that had been buried for more than a year.

  • He's even used a bite mark

  • taken out of a bologna sandwich to get a conviction.

  • Now, that sounds impressive matching a killer's teeth

  • to a bite mark in a bologna sandwich,

  • although, you should know that the defendant in that case,

  • got a new trial after an autopsy report

  • found that the murder victim

  • had actually eaten a small amount of bologna

  • consistent with the amounts bitten off the sandwich.

  • -(AUDIENCE LAUGHING) -So, that sandwich,

  • was irrelevant to the case.

  • In fact, you could even argue that it was actually Dr. West,

  • who was full of, say it with me,

  • -shit. -(AUDIENCE LAUGHING)

  • And-- that is not the only issue

  • that has arisen from his testimony.

  • There are now five cases

  • where he testified for the prosecution

  • and where the charges were dropped

  • or the conviction was later over turned

  • and even West himself

  • has admitted that he no longer believes

  • in bite mark analysis for identifying perpetrators

  • and he doesn't think it should be used in court.

  • And yet, incredibly,

  • every time a defendant has challenged its validity

  • the court has ruled it admissible.

  • And a key reason for that

  • is that judges often rely on precedent

  • to decide what to allow in front of a jury. So,

  • if a particular discipline has been in court before

  • it is likely that a judge will admit it again.

  • All of which means that as the co-founder

  • of the Innocence Project points out,

  • decisions about the validity of science are being made

  • by people who don't necessarily know much about it.

  • Historically, we had a situation where,

  • two scientifically illiterate lawyers

  • argued the bonafides of scientific evidence

  • before a scientifically illiterate judge,

  • so the 12 scientifically illiterate jurors

  • could decide the weight of that evidence.

  • And if you think about it, that's absolutely terrifying.

  • Trials can often be a situation when no one

  • really knows what they are doing.

  • It's like a cooking competition for toddlers,

  • hosted by a stray cat and judged by goats.

  • -(AUDIENCE LAUGHING) -Oh.

  • The tuna was under cooked

  • and covered in cold spaghetti sauce.

  • You then for some reason

  • cover the whole dish in honey nut cheerios.

  • -I loved it. -(AUDIENCE LAUGHING)

  • And look, none of this is to say,

  • that there is not reliable forensic science out there.

  • Finger prints and DNA

  • are obvious examples but while we think of them as perfect,

  • it is important to know

  • they are by no means infallible.

  • The FBI has found fingerprint analysis

  • could have a false positive rate

  • as high as one error in 306 cases.

  • And a dramatic example of this

  • came after the Madrid's train bombings in 2004

  • when the FBI arrested this Oregon man, Brandon Mayfield.

  • He had never even been to Spain in his life.

  • But, three separate examiners, matched his finger prints

  • to one on a bag of detonators. So, he was at that point,

  • completely fucked!

  • Until, investigators happen to determine that,

  • that fingerprint actually also matched someone else

  • who was in Spain at the time and that blew the minds

  • of finger print experts.

  • MARK ACREE: We always assume

  • that finger prints are very very unique,

  • but what the Mayfield case demonstrates, is that

  • parts of a fingerprint can be

  • so similar, it's possible for two people to be

  • identified to one print.

  • That's true.

  • It turns out that two people can have finger prints

  • that are so close that even experts can't tell them apart.

  • Meaning that we are now this close

  • to finally proving my theory. There is only one Olsen twin.

  • She's just moving very fast

  • -back and forth. -(AUDIENCE APPLAUDING)

  • She confuses your eye.

  • Now, I don't know how this new information helps me, yet,

  • but when it does, the end is-- No! You frauds! You frauds!

  • (AUDIENCE APPLAUDING)

  • And then-- there is DNA,

  • which is the gold standard in forensic science for a reason

  • because in perfect conditions

  • it's seen as the most reliable form of evidence, but

  • not all DNA tests are equal

  • and crime scenes can produce DNA of widely varying quality.

  • NARRATOR 2: DNA is very fragile and easily mixed up

  • at a messy scene.

  • BRAD HART: So, imagine you come across a crime scene.

  • You may have a pool of blood

  • but