Speaker 1: Welcome to Stuff to Blow Your Mind from how Stuffwork
Speaker 1: dot Com. Hey, welcome to Stuff to Blow Your Mind.
Speaker 1: My name is Joe McCormick, and I'm Christian Sager, and
Speaker 1: our regular host Robert Lamb is out on vacation. So
Speaker 1: Christian and I are returning to finish our discussion about
Speaker 1: science and pseudoscience and criminal investigation and the justice system.
Speaker 1: So if you haven't heard part one yet, you should
Speaker 1: go back and listen to that first so you can
Speaker 1: understand what we're going to be talking about in this episode. So,
Speaker 1: without further ado, here is the second half of our conversation.
Speaker 1: So Christian, yeah, tell me about fingerprint analysis and ballistics matching. Okay,
Speaker 1: So fingerprint analysis is one of those ones that, like,
Speaker 1: you know, especially based on the C S I effect,
Speaker 1: like a lot of us just assume, like, yeah, well
Speaker 1: that's that's accurate, right, Like your your fingerprint is your fingerprint.
Speaker 1: Everybody's got a unique snowflake, and uh like how hard
Speaker 1: that's got to be bulletproof? Right, No pun intended. There's
Speaker 1: a little bit of wiggle room there, right, So legal
Speaker 1: experts are concerned. Actually there's inaccuracies in something that's called
Speaker 1: the friction ridge analysis that's used in fingerprint identification. So
Speaker 1: fingerprints are believed to be unique. The process of matching them, however,
Speaker 1: isn't statistically valid, mainly because prints on an ink pad
Speaker 1: are compared to smudged or partials, which you always hear
Speaker 1: that on shows right, we only got a partial, right
Speaker 1: that that's the stuff that's often found at crime scenes.
Speaker 1: Fingerprint examiners often testify, however, with absolute certainty. This isn't
Speaker 1: like like when you watch I don't know, like a
Speaker 1: like a Batman movie or something like that, and he
Speaker 1: finds a fingerprint and he runs it through the bat
Speaker 1: computer and it's like finds all those points of agreement
Speaker 1: and it's a perfect match. But in those examples, it's
Speaker 1: usually like a very clear fingerprint matched against a very
Speaker 1: clear fingerprint. What if it's a kind of smudge fingerprint
Speaker 1: match against a partial, kind of smudged fingerpot exactly, it's
Speaker 1: it's much harder to tell, and it's not with absolute certainty.
Speaker 1: A two thousand six study by the University of Southampton
Speaker 1: in England asked six veteran fingerprint examiners to study prints
Speaker 1: taken from their own cases without even telling them where
Speaker 1: these came from their results were totally inconsistent. Only two
Speaker 1: of the six reached the same conclusion that they had
Speaker 1: come to on the second examination. On the first a
Speaker 1: pattern recognition expert at Sunny Buffalo is actually developing software
Speaker 1: to quantify the certain the certainty of fingerprint matches. So
Speaker 1: it's kind of the back computer metaphor that we were
Speaker 1: just using. Right, So if you had an automated method, uh,
Speaker 1: and it was scientifically valid at the beginning, that would
Speaker 1: take sort of the subjectiveness out of it. Well, and
Speaker 1: that but also I mean think about it, like it
Speaker 1: could also easily tell you how what thecentage of accuracy
Speaker 1: was versus rather than like, I don't know, it was
Speaker 1: sort of the same, you know, like the well, that's
Speaker 1: what I talked about earlier, how it's important to have
Speaker 1: numerical quantities to deal with rather than just letting people
Speaker 1: go with their gut feeling. Right. So if this program
Speaker 1: works the way it's supposed to work, right, it could say, well,
Speaker 1: it's got twenty six percent match or it's got a
Speaker 1: nine percent match. You know, you just you can't do
Speaker 1: that as a human being with your eyes. And that's
Speaker 1: essentially what we've been relying on. Right, is like, well
Speaker 1: I looked at that one. That I looked at that one,
Speaker 1: and I've been doing this for twenty years. They looked
Speaker 1: the same to me. So boom, absolute certainty, you know.
Speaker 1: And that's a little bit like more complicated than it's
Speaker 1: portrayed to be. Ye, same thing happens with ballistics matching again.
Speaker 1: Another Yeah, Batman's coming up all over the place in
Speaker 1: this one, right, Like was it the Dark Knight where
Speaker 1: they were like doing the ballistic right, get that brick
Speaker 1: and he finds the bullet and then he matches it
Speaker 1: to It's ridiculous. Um. Ballistics matching is often done the
Speaker 1: same way, based on the theory that when a bullet
Speaker 1: is fired from a gun, it leaves unique marks on
Speaker 1: the slug by the guns barrel, but there's no standards
Speaker 1: to constitute what operates as a match between bullets. The
Speaker 1: National Research Council has actually called ballistics testing into question
Speaker 1: and that they say, look, it's neither unique nor is
Speaker 1: it reproducible, so why should we be using this in
Speaker 1: the court. A lab in Saint Paul, Minnesota, this is
Speaker 1: one of the ones I mentioned earlier was found with
Speaker 1: major errors that impacted their fingerprint and other evidence processing.
Speaker 1: This included sloppy documentation, dirty equipment, as well as a
Speaker 1: lack of basic scientific procedure. They actually used Wikipedia as
Speaker 1: technical reference. In one case, there was no clean area
Speaker 1: designated for Roobe for review even for their DNA evidence. So,
Speaker 1: for instance, like we've been saying, you know, we'll talk
Speaker 1: about it later at the end of the episode, but
Speaker 1: we've been saying DNA evidence is is pretty good, right,
Speaker 1: But when you've got like a pig style of a
Speaker 1: work environment and there's no clean area to review the
Speaker 1: d N a, yeah, it could be tainted. Yeah, And
Speaker 1: so these are basic problems with the just like the
Speaker 1: environment and procedure of analysis. They might not even be
Speaker 1: problems necessarily with the underlying theory that they're using to
Speaker 1: uh to determine the outcomes, though there might be problems
Speaker 1: there to be, yeah, exactly, So when you combine the
Speaker 1: two it gets even worse. Right, So, like ballistics matching
Speaker 1: or fingerprint matching, it's not always a d percent certain
Speaker 1: there's it's not absolute. And then you throw in the
Speaker 1: idea that well, like maybe this fingerprint technician is also
Speaker 1: like spilling. I don't know, like a HOGI on his fingerprint.
Speaker 1: Uh slides you know everything goes out the window. Yeah,
Speaker 1: let us committed this crime, right. Uh So I want
Speaker 1: to talk about fire analysis. Yeah, I don't know. It
Speaker 1: doesn't want to look at fire. It's it's a glowing
Speaker 1: god that draws all of us to it. But so,
Speaker 1: getting a joking aside for a minute, this is pretty serious. Actually.
Speaker 1: In February two four, a man named you may have
Speaker 1: heard about this, A man named Cameron Todd Willingham was
Speaker 1: put to death in Texas after being convicted of murdering
Speaker 1: his three children by arson. I have not heard of this, Okay.
Speaker 1: According to the charges, Williams set fire to his own
Speaker 1: house with his children trapped inside in order to kill them.
Speaker 1: And Uh, if you've heard about this case before, it
Speaker 1: was probably likely from one of the many articles and reports,
Speaker 1: maybe the most famous among them being this two thousand
Speaker 1: nine article in The New Yorker called Trial by Fire
Speaker 1: by David Grant. Uh. And they're all making the case
Speaker 1: that the state of Texas had very likely in this case,
Speaker 1: executed an innocent man. So why were people saying this? Well,
Speaker 1: the main thrust of the cases against the case against
Speaker 1: william were the only solid pieces of evidence against him
Speaker 1: were Number one, the testimony of a jail house informant
Speaker 1: of the criminal informants are sort of notoriously those are
Speaker 1: the cis that we were really talking about yeah, unreliable,
Speaker 1: yeah uh, and that that's that testimony itself has been
Speaker 1: subsequently called into question in this case, and a fire
Speaker 1: investigation concluding that the fire showed signs of deliberate arson
Speaker 1: pointing to the defendant, how do you come up with that? Well,
Speaker 1: I'm gonna get into it. So this fire analysis has
Speaker 1: been roundly criticized by experts as being pretty much without
Speaker 1: any scientific marriage. So I'm about to quote from David
Speaker 1: Grand's New Yorker article in a section where he describes
Speaker 1: this scientist and fire investigator named Dr. Gerald Hurst's reaction
Speaker 1: to what was happening in the field during fire investigations. Okay, quote.
Speaker 1: By the nineties, Hurst had begun devoting significant time to
Speaker 1: criminal arson cases, and as he was exposed to the
Speaker 1: methods of local and state fire investigators, he was shocked
Speaker 1: by what he saw. Many arson investigators, it turned out,
Speaker 1: had only a high school education. In most states, in
Speaker 1: order to be certified, investigators had to take a four
Speaker 1: our course on fire investigation, and pass a written exam.
Speaker 1: Often the bulk of an investigator's training came on the job,
Speaker 1: learning from Quote old timers in the field who passed
Speaker 1: down a body of wisdom about the telltale signs of arson,
Speaker 1: even though a study in nineteen seventy seven warned that
Speaker 1: there was nothing in the scientific literature to substantiate their validity,
Speaker 1: and then later in the piece Grand Rights quote in
Speaker 1: nineteen seven, the International Association of Arson Investigators filed a
Speaker 1: legal brief arguing that arson sleuths should not be bound
Speaker 1: by a nineteen nine Supreme Court decision that's probably referring
Speaker 1: to Daubert there Um, requiring experts who testified at trials
Speaker 1: to adhere to the scientific method. What arson sleuths did,
Speaker 1: the brief claimed, was quote less scientific. By two thousand,
Speaker 1: after the courts had rejected such claims, arson investigators increasingly
Speaker 1: recognized the scientific method, but there remained a great verys
Speaker 1: in the field, with many practitioners still relying on the
Speaker 1: unverified techniques that have been used for generations. Quote. People
Speaker 1: investigated fire largely with a flat earth approach. Hurst told
Speaker 1: me that this means the common sense thing that we
Speaker 1: were talking about earlier. Yes, exactly, the quote continues, it
Speaker 1: looks like arson, therefore it's arson, he went on. My
Speaker 1: view is you have to have a scientific basis otherwise
Speaker 1: it's no different than witch hunting. I know arson when
Speaker 1: I see it right now. I don't claim to know
Speaker 1: one way or another about willing him personally, whether he
Speaker 1: was guilty or innocent. But this does make a close
Speaker 1: look at the field of fire analysis very worthwhile. Uh And,
Speaker 1: and I want to point out that, like pretty much
Speaker 1: all of these others in theory, fire analysis is a
Speaker 1: perfectly legitimate field of study. It's not for anology. It's
Speaker 1: not just wrong from the ground up. So what might
Speaker 1: a fire investigation look like? Often it involves searching through
Speaker 1: the remains of a burned building for indications of how
Speaker 1: a fire was started, what course it took once it
Speaker 1: was ignited. Um And in forensic investigation, for fairly obvious reasons,
Speaker 1: this often involves looking for indications of arson. You're trying
Speaker 1: to figure out, did somebody set this fire or did
Speaker 1: it happen accidentally? Uh And if you can find evidence
Speaker 1: that accelerants such as gasoline or lighter fluid, where used
Speaker 1: to start the fire. That's one of the most common
Speaker 1: indications of varson, of deliberate intention in the fire. But unfortunately,
Speaker 1: in practice, some fire investigators have been known to use
Speaker 1: these highly faulty techniques that are not established to have
Speaker 1: any scientific validity. It's just like we're saying earlier, kind
Speaker 1: of like folk knowledge. The investigators pass it down, but
Speaker 1: there's never been a study dedicated to figuring out whether
Speaker 1: these rules of analysis are true or not. So in
Speaker 1: a short article in September, the skeptic writer Michael Schermer
Speaker 1: reported a conversation he had with a guy named John
Speaker 1: Jay Lntini, who is a fire analysis expert and the
Speaker 1: author of this this criminal this forensics textbook called Scientific
Speaker 1: Protocols for Fire Investigation. So this is a guy who's
Speaker 1: taking the scientific approach, and Lean Teeny tells him that
Speaker 1: lots of fire investigators follow scientifically baseless folk wisdom, such
Speaker 1: as that so called alligator ing can indicate whether a
Speaker 1: fire burned fast or slow. And this alligator ing, this
Speaker 1: this idea is that it's it's like looking at an
Speaker 1: alligator's hide. So you look at wood that burned during
Speaker 1: a fire, and if you look at it and you
Speaker 1: see small flat blisters, that means that the fire burned
Speaker 1: quote slow. And if you see large shiny blisters, that
Speaker 1: means that it burned quote fast. Lntini his analysis of
Speaker 1: this rule is quote nonsense. Yeah. Ok, that nobody's actually
Speaker 1: measured that essentially, and then we quantified it and published
Speaker 1: papers that we can refer back to. Right. Also, according
Speaker 1: to len Tina, it used to be fire investing gator
Speaker 1: wisdom that when you see crazing and window glass, you
Speaker 1: know what crazing is. It's like when you see these, uh,
Speaker 1: these sort of crazy spiderweb patterns virgin not exactly, not
Speaker 1: like the circular spiderwebs, but just cracks all through the glass,
Speaker 1: crazy all over the place. Right, This glass is now
Speaker 1: legally insane. Yeah, So they uh, they used to say
Speaker 1: that this was an indicator that the glass had been
Speaker 1: heated very rapidly, which would indicate the use of an accelerant.
Speaker 1: It heated rapidly because somebody squirted gasoline or lighter fluid
Speaker 1: all over the place. In fact, that's not true, and
Speaker 1: it turns out after scientific investigation that window crazing is
Speaker 1: caused by the opposite. It's caused by rapid cooling, like
Speaker 1: what would happen when firefighters douse the area with water. Okay,
Speaker 1: I can picture this, yeah yeah. Um. Also another thing
Speaker 1: that's common puddle shaped burns on the floor that can
Speaker 1: make it look certainly like there was an ignited pool
Speaker 1: of liquid on the floor, like somebody emptied a gas
Speaker 1: can all over the place set it on fire. According
Speaker 1: to Lenten E wrong again, even though fire and heat
Speaker 1: do tend rise when an entire room burns, the floor
Speaker 1: burns along with it, and these marks can appear without
Speaker 1: the presence of an accelerant. Um. So, fire analysis is
Speaker 1: one of the forensic fields addressed in this two thousand
Speaker 1: nine in our C report, and they conclude that while
Speaker 1: there is a fairly solid basis for explosion analysis like
Speaker 1: when a bomb goes off, fire analysis is much shakier
Speaker 1: than explosion analysis is as practice today. Um. They say,
Speaker 1: quote many of the rules of thumb that are typically
Speaker 1: assumed to indicate that an accelerant was used e g.
Speaker 1: Alligatoring of wood specific char patterns have been shown not
Speaker 1: to be true. Experiments should be designed to put arson
Speaker 1: investigations on a more solid scientific footing. Uh. And again
Speaker 1: this is just crazy. I mean, this is yet another
Speaker 1: one of these that has been used to convict people,
Speaker 1: like in the case of William So we don't know,
Speaker 1: I guess whether he was guilty or innocent, But if
Speaker 1: this was the main evidence to show he was guilty,
Speaker 1: that's that makes it look pretty bad. Yeah, that's kind
Speaker 1: of stuff is depressing, especially like when you I don't
Speaker 1: know if you watched Making a Murderer, right, when you
Speaker 1: watch these like long form documentaries about the justice system
Speaker 1: and just how flawed it is. Not saying that in
Speaker 1: that particular case, I know whether anybody is guilty or
Speaker 1: innocent or anything, but it's you think about how often
Speaker 1: this stuff goes on and then you've got examples like this.
Speaker 1: It's heartbreaking. Uh. This section though, highlights one thing I
Speaker 1: do want to emphasize again where we don't want to
Speaker 1: paint all forensic science professionals and experts in these fields
Speaker 1: with a with a you know, tainted brush, I mean,
Speaker 1: and also saying here like most of them are doing
Speaker 1: the best they can with what they have available to
Speaker 1: him exactly, and in this case, the bad forensic science
Speaker 1: and fire investigation is being exposed by good scientists and
Speaker 1: fire investigation so it's not like everyone in this field
Speaker 1: is doing a bad job of it, but many people
Speaker 1: who are practicing it are. Yeah, this is truly a
Speaker 1: wicked problem. I wish we had more money to divide
Speaker 1: to divert into research and resources for stuff like this. Yeah. Well,
Speaker 1: hair analysis is one of the ones we brought up
Speaker 1: at the top because that was actually one of the
Speaker 1: hair and fiber was one of the things we're talking about,
Speaker 1: Josh about. Yeah, we're and we were also like, maybe
Speaker 1: we'll do something like that in our little like video series,
Speaker 1: and then the more we start to look into it,
Speaker 1: we're like, I don't know about this, this is a
Speaker 1: little hokey. Well okay, so one thing I can say is,
Speaker 1: if you find a perpetrator's hair at the crime, couldn't
Speaker 1: you use that to do some DNA analysis? That would
Speaker 1: be pretty conclusive. I don't know, I would think so.
Speaker 1: But again, remember the statistics on how often they use
Speaker 1: DNA and say versus something like this, probably because of
Speaker 1: the timing and the money involved. Yeah, um, whereas like
Speaker 1: to just look at two fibers and have somebody come
Speaker 1: in as an expert and say, yep, it's a match.
Speaker 1: Seems easier to a lot of people, I would guess
Speaker 1: are cheaper. Okay, what happens when there is hair matching
Speaker 1: or hair fiber analysis. Well, I want to back up,
Speaker 1: because there was just last year the Justice Department and
Speaker 1: the FBI formally acknowledged that nearly every examiner in the
Speaker 1: FBI's laboratory on microscopic hair comparison gave flawed testimony in
Speaker 1: the trials that they offered evidence. And this is over
Speaker 1: the course of two decades. This is huge. It's like
Speaker 1: the biggest UH scandal in forensic science to date as
Speaker 1: far as I can tell. Um. They were giving statements
Speaker 1: that were quote, beyond the bounds of proper science. What
Speaker 1: they were basically doing was saying there's a hundred percent
Speaker 1: match between two hair fibers or a hair fiber found
Speaker 1: on the scene the hair from you know, a defendant, uh,
Speaker 1: when there's just a similarity. So they're totally misleading. The
Speaker 1: jury's twenty six out of the twenty eight overstated forensic
Speaker 1: mass matches favor the prosecutors, of course, because they're working together.
Speaker 1: This equated to nine of the two hundred sixty trials.
Speaker 1: According to the National Association of Criminal Defense lawyers and
Speaker 1: the Innocence Project. This is the nation's largest post conviction
Speaker 1: review of question forensic evidence. It's crazy. Of these cases,
Speaker 1: thirty two defendants were sentenced to death. Fourteen have already
Speaker 1: been executed or died in prison. So that's I mean,
Speaker 1: whether they were innocent or guilty, we don't know, but
Speaker 1: they don't yeah, and we'll never have a chance. Now
Speaker 1: the cases against them have been undermined. And keep in
Speaker 1: mind that just because the FBI made these errors, there
Speaker 1: was other evidence used to convict these defendants of guilt. Okay,
Speaker 1: so it wasn't the only thing. But still each case
Speaker 1: has to be reviewed to see if there are grounds
Speaker 1: for an appeal. Four were previously exonerated, So this is
Speaker 1: a landmark revelation that pattern based forensic techniques, things like
Speaker 1: hair bite mark analysis, ballistics largely subjective, and these contributed
Speaker 1: to more than twenty five of the three hundred and
Speaker 1: twenty nine cases where a defendant has been exonerated with
Speaker 1: DNA analysis post conviction. So that's how DNA analysis has
Speaker 1: been used very much in the last like ten to
Speaker 1: twenty years. Well, we talked about the exclusionary principle earlier,
Speaker 1: you know, a lot of what DNA evidence is actually
Speaker 1: brought to the field is uh, not just matching and
Speaker 1: saying here, you know this criminal, definitely, that's that's his
Speaker 1: or her blood there, but excluding people saying, look, this
Speaker 1: is not their day genetic material. Yeah, this is not
Speaker 1: a match. So a lot of politicians weighed in on this.
Speaker 1: Of course, they asked the FBI to do a systematic
Speaker 1: analysis to breakdown their system, and the FBI says that
Speaker 1: their hair examiners lacked written standards that defined what were
Speaker 1: the appropriate ways to explain their results in court. That
Speaker 1: was until two thousand and twelve. This all came to
Speaker 1: light after the Washington Post reported on flawed forensic hair
Speaker 1: match is. Federal authorities investigated this and they found it
Speaker 1: to be true. They found that the experts quote unquote
Speaker 1: that we're testifying to near certainty of matches in a
Speaker 1: crime scene, they were citing incomplete and misleading statistics drawn
Speaker 1: from their own work. So I want to make this clear,
Speaker 1: there is no accepted research on how hair from different
Speaker 1: people can appear the same. So, I mean, like you
Speaker 1: asked at the topic, well, how does that work? I
Speaker 1: mean I think it's literally like you look under a
Speaker 1: microscope at the two pieces of hair, and that looks
Speaker 1: similar to me. Yeah, And I mean I'm sure that
Speaker 1: there's some more to it than that, right, in the
Speaker 1: same way as like there's some old timey wisdom passed
Speaker 1: down about how fires look the same, right, but there's
Speaker 1: no accepted research that one one thing leads to another.
Speaker 1: Even before this, the FBI reported it's examiners were reporting
Speaker 1: false hair matches more than eleven percent of the time,
Speaker 1: and at the time of this report, five defendants were
Speaker 1: exonerated through d in a testing, all of whom had
Speaker 1: served between twenty and thirty years in prison for either
Speaker 1: rape or murder. Jeez, I mean, this is just, again,
Speaker 1: like I said, heartbreaking. Of twenty one thousand federal or
Speaker 1: state requests for hair comparison evidence from nineteen seventy two
Speaker 1: to nineteen ninety nine, the FBI found that two thousand,
Speaker 1: five hundred of those cases had examiners declare hair matches.
Speaker 1: They're reviewing every single one of those cases now, like
Speaker 1: they have to go back and just review everything. The
Speaker 1: same examiners who are now under review also taught five
Speaker 1: hundred to a thousand state and local crime analysis labs
Speaker 1: how to testify in the same way. So this is
Speaker 1: like the old timers passing down the wisdom, and so
Speaker 1: it's an endemic problem. It's not just the FBI, it's
Speaker 1: everywhere now. So these same testimonies were likely flawed at
Speaker 1: the same level. It's just it's it's insane. In one
Speaker 1: shocking example, this is just one example of how it
Speaker 1: affected a person, a lot person's life. Sante Tribble served
Speaker 1: twenty eight years for murder based on FBI hair testimony.
Speaker 1: It later turned out that one of the hairs that
Speaker 1: was used to prosecute him came from a dog. Oh
Speaker 1: my god, he was exonerated in Wow, So hair analysis
Speaker 1: not so much bite mark analysis. Okay, here's another example.
Speaker 1: Expert in forensic odeontology, we mentioned that earlier testified that
Speaker 1: multiple bite marks found on a murder victim were entirely
Speaker 1: consistent with the dental impressions taken from a guy named
Speaker 1: Roy Brown. This was the only physical evidence in this case.
Speaker 1: Brown was sentenced to twenty five years to life in prison.
Speaker 1: DNA tests later confirmed that a second suspect was actually guilty,
Speaker 1: but Brown. He spent fifteen years in prison. So bite
Speaker 1: mark analysis is now also widely considered unreliable. Yeah, it
Speaker 1: was explored in the two is a nine in RC
Speaker 1: document and that they outlined several problems with current use
Speaker 1: of bite mark evidence. Uh, they say, quote, uniqueness of
Speaker 1: human dentition has not been scientifically established. I mean you'd
Speaker 1: think that that's pretty basic. You'd have to start with
Speaker 1: the study making it statistically clear that humans have unique
Speaker 1: bite marks. But I mean, what if they don't usually
Speaker 1: have unique bite marks. I mean, I don't know what
Speaker 1: you would expect bite marks to look like. Maybe lots
Speaker 1: of people have very similar looking bite marks. And I
Speaker 1: would also think that again, like this is I haven't
Speaker 1: done research on this, but I would imagine that the
Speaker 1: force of the bite would contribute to what the bite
Speaker 1: marks look like. Well, that's another thing. So they say,
Speaker 1: even if dentition is unique, even if everybody has a
Speaker 1: unique bite mark in the same way that it's commonly
Speaker 1: assumed people have unique fingerprints. Uh, the ability of the
Speaker 1: person to transfer a unique pattern to human skin, and
Speaker 1: then the ability of the skin to maintain the uniqueness
Speaker 1: of that pattern has not been scientifically established. So, so
Speaker 1: imagine just what happens when people are trying to analyze
Speaker 1: a bite mark on skin that maybe sagging or distorting
Speaker 1: the bites. The marks might not leave a clear impression
Speaker 1: that's still there when the forensic scientist gets a picture
Speaker 1: of it or gets to examine it. I don't even
Speaker 1: know how you test this, like, well, I meanlock style,
Speaker 1: Like you get like some molds of teeth and then
Speaker 1: you take like a corpse and and have the molds
Speaker 1: bite the corpse several times and see how they line up. Yeah,
Speaker 1: I think you'd have to. You'd have to examine it
Speaker 1: statistically with a large sample size, just testing different Yeah,
Speaker 1: different molds of teeth or something like that. I don't know,
Speaker 1: if you test on dead people's bodies or something like that. Well,
Speaker 1: I don't know. I mean, it's the thing. I admit
Speaker 1: this is difficult to test, but this is this is
Speaker 1: ground level research that should be done if you're going
Speaker 1: to be using this to convict people. Oh yeah, yeah,
Speaker 1: yeah absolutely, or to defend people either way. All right,
Speaker 1: so you're ready for the big one. Yeah, So DNA
Speaker 1: analysis we established at the beginning, and I think this
Speaker 1: is true, is widely considered, and I think with good reason,
Speaker 1: the most reliable forensic science field. When you when you're
Speaker 1: matching DNA evidence, you can know if the if the
Speaker 1: procedures have been carried out carefully and and all of
Speaker 1: the protocols have been followed, that if you have a
Speaker 1: DNA sample of the crime scene, and you have a
Speaker 1: DNA sample from the defendant, you can know, you know,
Speaker 1: beyond a one in billions chance of error, that this
Speaker 1: is the same person or it's not the same person. Yeah.
Speaker 1: Except The Atlantic published an article this year called a
Speaker 1: reasonable doubt. Uh, and it said exactly that it starts
Speaker 1: off and saying yes. D NA analysis has long been
Speaker 1: held as the exception to the rule about forensics. Arose
Speaker 1: from academics. It's been studied and validated by researchers all
Speaker 1: around the world. Uh, just a little history here. It
Speaker 1: was pioneered by British geneticist named Alec Jeffreys. He was
Speaker 1: looking into genetic sequencing and he applied it in the
Speaker 1: field with police to help solve a pair of murders
Speaker 1: in the British Midlands. Following that, several private companies in
Speaker 1: the US and the UK opened their own forensic DNA labs.
Speaker 1: But defense teams have argued against it for years. Well why, Well,
Speaker 1: the first thing they said was, at first DNA analysis
Speaker 1: actually didn't pass the fry test. I can understand when
Speaker 1: it's new, it's not generally accepted yet. Yeah, they set
Speaker 1: a legal standard requiring scientific evidence to have widespread acceptance
Speaker 1: in his field was needed. Okay, well we have that now.
Speaker 1: Academics complained that these firms weren't actually being transparent about
Speaker 1: their testing technique. Well, our methodology wasn't. Well, that's a
Speaker 1: perfectly acceptable concern. I think anybody doing this kind of
Speaker 1: analysis should be making public exactly what their methodologies are.
Speaker 1: And then, as we've well, I maybe not all of us.
Speaker 1: I I was paying attention to the news at the time,
Speaker 1: but as popularized by the O. J. Simpson trial, the
Speaker 1: argument that DNA samples can in fact be contaminated during
Speaker 1: both collection or in the crime lab. But throughout the years,
Speaker 1: the thoroughness of labs and analysis list they all got better, right,
Speaker 1: so so much so that the Innocence Project, which we've
Speaker 1: been mentioning over and over again this episode, was founded
Speaker 1: in because they were absolutely convinced that DNA evidence could
Speaker 1: exonerate questionable convictions. They have since won one hundred and
Speaker 1: seventy eight exonerations due to DNA testing. In a book
Speaker 1: by the founders of the Innocence Project, they said, quote,
Speaker 1: DNA testing is to justice what the telescope is for
Speaker 1: the stars. But yeah, I think in many ways that's true.
Speaker 1: And now we're gonna say what the flaws are. But overall,
Speaker 1: DNA testing, I will agree, is super solid. Yeah, yeah, no,
Speaker 1: I think you're right too. But it's important to sort
Speaker 1: of lay this out to know that there are problems
Speaker 1: with it. Uh So this has been amplified, of course
Speaker 1: by the c s I effect that we've also been
Speaker 1: talking about, right the expectation of jurors to see DNA
Speaker 1: evidence in corn cases. In fact, in two thousand and eight,
Speaker 1: there was a study done by a felony judge in
Speaker 1: Michigan where he randomly pulled a thousand, twenty seven summon jurors,
Speaker 1: and seventy five percent of them expected that they would
Speaker 1: see DNA in a rape case. Fifty of them expected
Speaker 1: that in a murder or an attempted murder case. They
Speaker 1: would see DNA in expected they would see it in
Speaker 1: any criminal case that they were a part of. The
Speaker 1: DNA was just so widely available to research and use
Speaker 1: as evidence that of course it would pop up. Yeah,
Speaker 1: and this has got to be frustrating to I mean,
Speaker 1: well meaning prosecutors. Who are you know, they're they're not
Speaker 1: trying to cut corners or something, But in many cases
Speaker 1: DNA evidence just might not be available. Well, and the
Speaker 1: other side of it, too, is that DNA has become
Speaker 1: such a powerful tool in the courtroom that it almost
Speaker 1: automatically secures convictions, right because people hear those words d
Speaker 1: N A and they're just like, well, that's irrefutable. Well,
Speaker 1: I mean, I can say if if there's a murder
Speaker 1: case and uh, and there are blood stains found on
Speaker 1: a victim, and you can take those blood stains and
Speaker 1: and several different DNA analysis labs, I'll say that it's
Speaker 1: a perfect match for the defendant. I think it's pretty
Speaker 1: likely that looks like guilt to me. You should watch
Speaker 1: Making a Murderer Man, because there's a whole thing in
Speaker 1: that about how like they found this guy's blood at
Speaker 1: a at a crime scene in a car. And then
Speaker 1: the argument is made, well, the police actually had access
Speaker 1: to his blood from previous case. They may have planted
Speaker 1: the blood there. Well, in that case, that's I would
Speaker 1: say that's again not a problem with the scientific methodology,
Speaker 1: but a problem with the with the investigation and the procedures. Yeah,
Speaker 1: like you're right, so okay. Research from Australia found that
Speaker 1: sexual assault cases involving DNA evidence were twice as likely
Speaker 1: to reach trial and thirty three times is likely to
Speaker 1: result in a guilty verdict. There's DNA right. Homicide cases
Speaker 1: fourteen times is likely to reach trial, twenty three times
Speaker 1: is likely to end in a guilty verdict. Another major
Speaker 1: study in the UK found that just the knowledge that
Speaker 1: prosecution intended to introduce DNA evidence before it was even
Speaker 1: actually like introduced in a case was enough to get
Speaker 1: a defendant to capitulate because they're just like, okay, so
Speaker 1: there's questions about collection and storage, but they just they
Speaker 1: just stopped because what do you mean stopped? Well, because
Speaker 1: people were starting to think, like, well, this is just
Speaker 1: irrefutable evidence. Why should we bother looking at the collection
Speaker 1: and storage of it. DNA is just winning so many cases,
Speaker 1: let's not bother with it. So as the cases we
Speaker 1: use DNA evidence and become more complicated, it actually becomes
Speaker 1: less of an objective science. And I'll give you an
Speaker 1: example here so just real quick primer on this, nine
Speaker 1: percent of our genes are the same as every other
Speaker 1: human on the planet. My genes are the same as
Speaker 1: Joe's jeans. But the DNA analysts know this, of course,
Speaker 1: So we need to look for things that are called alleles.
Speaker 1: They're very specific locations on each DNA strand that vary
Speaker 1: from individual to individual, the different versions of a gene
Speaker 1: in the different places on your chromosomes. The standard is
Speaker 1: to compare alleles at thirteen locations. Now, if you do
Speaker 1: it that way, the odds of two unrelated people matching
Speaker 1: are less than one in a billion, So that's pretty good, right,
Speaker 1: But what happens if you're looking at a case and
Speaker 1: it involves a third person, So you're not just comparing
Speaker 1: two DNA, you're comparing three, or what if you're comparing four?
Speaker 1: What if there are four people at the scene. Figuring
Speaker 1: out which alleles belong to whom becomes more complicated the
Speaker 1: more people that are involved, And if a sample is
Speaker 1: small or degraded, which they often are from crime scenes,
Speaker 1: the alleles might drop out in some locations as well.
Speaker 1: So there's a study done by a guy's name a
Speaker 1: teal drawer and Greg hamp A key in they took
Speaker 1: DNA paperwork from a two thousand to Georgia rape trial
Speaker 1: here in the state that we're recording this in. They
Speaker 1: gave the evidence to seventeen technicians without context. All of
Speaker 1: these people were experienced DNA technicians with an average of
Speaker 1: nine years in the field. They were asked to determine
Speaker 1: if the DNA was from the defendant in the case.
Speaker 1: Only one of the seventeen people concurred that it was
Speaker 1: the defendant, twelve said it was exclusionary, for said it
Speaker 1: was totally inconclusive. Since this example, there have been accounts
Speaker 1: of dozens of DNA typing cases that have gone wrong,
Speaker 1: especially because it's so easily contaminated depending on who comes
Speaker 1: in contact with it. Right. So there's something that's called
Speaker 1: d N A transfer which contributes to this the most.
Speaker 1: It's when cells migrate from people to people or from
Speaker 1: people to objects, inevitably when we just touched things. Right.
Speaker 1: Another study asked participants to shake hands for two minutes
Speaker 1: and hold a knife when the DNA on the knife
Speaker 1: was analyzed. Well, to be a participant there just sitting
Speaker 1: there holding the knife, and now you hold the knife.
Speaker 1: What do I do with it? Just hold it? Just
Speaker 1: hold it. Man. When the DNA on the knife was analyzed,
Speaker 1: the partner was identified as a contributor in the cases
Speaker 1: found them to be the sole contributor. They didn't even
Speaker 1: find the DNA from the second person. So going forward,
Speaker 1: more context needs to be around for this DNA analysis. Right.
Speaker 1: The science is is there, but it it's complicated and
Speaker 1: there needs to be like, I guess again, procedures put
Speaker 1: in place for like, well, how how do you what?
Speaker 1: What's the percentage of accuracy? I think is what we
Speaker 1: need to come down on. Uh. Houston, Oh boy, Houston.
Speaker 1: Houston had a real bad incident of this. Their crime
Speaker 1: lab handled DNA evidence from five cases a year. A
Speaker 1: local television station obtained dozens of the DNA profiles that
Speaker 1: were processed by this lab and they sent them to
Speaker 1: independent experts for analysis. It turned out that the technicians
Speaker 1: were routinely misinterpreting even the most basic of DNA samples.
Speaker 1: So this was just like a technician error, and the
Speaker 1: Innocence Project themselves said, well, we don't take cases where
Speaker 1: there are positive DNA matches. And one example, a tech
Speaker 1: created a profile for a victim from three different sets
Speaker 1: of DNA, the result profiles all totally varied. Then she
Speaker 1: mismatched the DNA from the crime scene and the accused defendants.
Speaker 1: This led to a retrial where the defendant was released.
Speaker 1: So this tech was fired. This is the same Houston
Speaker 1: lab she was fired. Then she was reinstated because her
Speaker 1: lawyer said, well, the problem was systemic. It was the
Speaker 1: whole lab in Houston that was the problem here. They
Speaker 1: had inadequate supervision. Well that may have been the case,
Speaker 1: it could have been. Yeah, but think about all five
Speaker 1: of those cases. I mean, we think that this DNA
Speaker 1: analysis is rock solid, and then you hear this and
Speaker 1: it's like, well, there's five cases we have to go
Speaker 1: back and review again. You know. So, oh man, this
Speaker 1: is so crazy because it's you think of scientific evidence
Speaker 1: as being the most reliable kind of evidence that you
Speaker 1: can have in a courtroom, at least I would, I think.
Speaker 1: But and and that's so scary that you often will
Speaker 1: have this problem of not knowing whether you can trust
Speaker 1: the expert witness telling you something because you don't know
Speaker 1: if there if there was something wrong with the data
Speaker 1: collection and contamination. You don't know if their methodologies are
Speaker 1: actually sound to begin with, whether they've been based on
Speaker 1: well tested scientific principles, do they have a clean lab.
Speaker 1: Is their supervisor pushing them to do more work than
Speaker 1: they're capable of doing exactly? Or is there is there
Speaker 1: prosecutorial bias or something. Is there pressure from the dep
Speaker 1: artment for them to uh basically convict more cases? Yeah?
Speaker 1: And man, that's so tough because we've already seen evidence
Speaker 1: in courtrooms undermined by lots of other kinds of studies.
Speaker 1: I mean, the more we learn about the reliability of
Speaker 1: eyewitness testimony, nothing ever makes it look more reliable. Uh. People,
Speaker 1: it just turns out, man, people's memories are not very good.
Speaker 1: And in many cases, people have they profess confidence in
Speaker 1: identifying a you know, a perpetrator or something in a courtroom,
Speaker 1: but then it turns out there wrong. And uh so,
Speaker 1: so eyewitness testimony. What I'm not saying it's always wrong,
Speaker 1: but it's just you can't be very confident in trusting it. Um.
Speaker 1: We we've seen all these problems with forensic science and
Speaker 1: so man, it is just it's just tough out there
Speaker 1: to know that you're getting the right answer in a courtroom.
Speaker 1: I would hate to be I would hate to be
Speaker 1: the defendant in any case, especially a case in which
Speaker 1: I was innocent. Right now, that's yecially if you're innocent, Yeah,
Speaker 1: I think, yeah, it's guilty. I'd still hate it, but
Speaker 1: I'd be like, but I did beat Joe down with
Speaker 1: the folding chair, Yeah exactly, But how are they going
Speaker 1: to tell bruise marks? There's no science that unless you're
Speaker 1: Sherlock and you're beating corpses with a horse whip, like
Speaker 1: I said, Uh, okay, jokes aside, Seriously, this is a
Speaker 1: big problem. What do we do, like, what's the future
Speaker 1: of this look like? How do we reform it? Well?
Speaker 1: One of the problems is that forensic science encompasses many
Speaker 1: different fields, right, so that lots all these fields have
Speaker 1: different standards, and some have different problems. Some are more
Speaker 1: solid than others, Some have more regulations in place to
Speaker 1: keep all of the practitioners in line than others do. So,
Speaker 1: so it's a it's a big, hairy, complicated problem, and
Speaker 1: there's not one simple prescription that will fix it all. Yeah,
Speaker 1: but there are some sort of general rules that some
Speaker 1: fields may already be following pretty well, and others could
Speaker 1: do a much better job of Yeah, some possibilities that
Speaker 1: people are throwing out as they're saying, defendants should have
Speaker 1: their own forensics experts that are paid for. Uh. There
Speaker 1: should be separate crime labs from the prosecutors and the
Speaker 1: police that they're answering to. And there should be, of course,
Speaker 1: as we've been alluding to all episode, an established system
Speaker 1: of verification and standards. Yeah. I mean one one hypothetical
Speaker 1: you could imagine would be something like that. There is.
Speaker 1: It would be sort of like the uh, forensic science
Speaker 1: version of public financing of elections, where you say, you know,
Speaker 1: like if you have mismatched resources going in, you can
Speaker 1: make this fairer if you just give both sides equal
Speaker 1: money from the government and that's what they have to
Speaker 1: spend on elections. Uh. In in this case, you could say, well,
Speaker 1: what if we just have a a crime lab that is,
Speaker 1: you know, big national crime lab that works for neither
Speaker 1: the defense nor the prosecution, and that in order to
Speaker 1: get forensic science that's admissible in court, you have to
Speaker 1: go through this this big uh, this big well regulated system,
Speaker 1: and that that they don't work for either side. Yeah.
Speaker 1: In fact, an independent entity that would be called the
Speaker 1: National Institute of forensic science has been recommended for something
Speaker 1: like this, and they would be responsible for both establishing
Speaker 1: the standards that we're talking about and for certifying people
Speaker 1: as experts. Another another way of helping the problem is
Speaker 1: just from the ground up in each field itself. Like
Speaker 1: we were talking about earlier in in fire analysis, they're
Speaker 1: very legitimate scientists working in this field who are just
Speaker 1: trying to improve the field by doing scientific research and
Speaker 1: holding others in their field accountable to pay attention to it. Yeah, yeah,
Speaker 1: that's true. Uh. There's also this one like case that
Speaker 1: came up about DNA, which is interesting. There's a company
Speaker 1: that's using software and automation to take the human element
Speaker 1: out of it completely, and I've alluded to that as
Speaker 1: well with like finger analysis things like that. Um, they're saying, well,
Speaker 1: we take the subjective decisions out of it, and the
Speaker 1: analyst is the one who's making the flawed conclusions. The
Speaker 1: company calls itself true Allele uh. And the software, however,
Speaker 1: has been criticized for whether it actually met the FRIES standard,
Speaker 1: even though we're no longer using the price standard is
Speaker 1: being criticized because it hasn't been accepted by the larger
Speaker 1: science community. But one thing I would say about that
Speaker 1: is I think if you have a computer program that's
Speaker 1: that's doing analysis on forensic science, I think that would
Speaker 1: need to be open source. And company who develops that
Speaker 1: probably isn't gonna want that because they're gonna want it
Speaker 1: to be proprietary own it. But that should be something
Speaker 1: that anybody can go look at the source code and
Speaker 1: make sure that it's working accurately and not biasing towards
Speaker 1: a certain conclusion. Okay, so that was a lot about
Speaker 1: forensic science, and unfortunately we don't this is already a
Speaker 1: long episode. We don't have time to two more here,
Speaker 1: and there were a bunch of other topics we wanted
Speaker 1: to get into and just didn't even have space for,
Speaker 1: like handwriting analysis, lie detection, the polygraph recovered memories. So
Speaker 1: maybe we can address those. If you're interested, you can
Speaker 1: write us and let us know you want to learn
Speaker 1: about them, and we'll talk about them in a future episode. Yeah,
Speaker 1: we can sit down record a future episode, maybe bring
Speaker 1: in old Robert Lamb and uh we could uh um. Also,
Speaker 1: like I would love to hear in the meantime from
Speaker 1: some of you who perhaps work in this field, you know,
Speaker 1: we have something to add to the discussion. Yes, is
Speaker 1: there anything we missed out on or that's a really
Speaker 1: interesting case of of of how these standards are enforced
Speaker 1: in the field that you're familiar with. So if you
Speaker 1: want to write into us about forensic science, you want
Speaker 1: to talk to us about maybe your experiences, maybe you've
Speaker 1: been on a jury like I have, or you work
Speaker 1: in forensic science lab and you have some argument perhaps
Speaker 1: with how we've portrayed the science here. Please let us know.
Speaker 1: We'd love to hear from you. We are all over
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