Instant Genius - Forensic anthropology, with Prof Sue Black

Episode Date: July 11, 2021

Prof Sue Black explains the science behind identifying a body at a crime scene. Warning: This episode contains a frank and academic discussion about forensic investigation – how it works and what clues a dead body might leave behind – which some listeners may find uncomfortable. Once you’ve mastered the basics with Instant Genius, dive deeper with Instant Genius Extra, where you’ll find longer, richer discussions about the most exciting ideas in the world of science and technology. Only available on Apple Podcasts. Produced by the team behind BBC Science Focus Magazine. Visit our website: sciencefocus.com Hosted on Acast. See acast.com/privacy for more information. Learn more about your ad choices. Visit podcastchoices.com/adchoices

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I'm Daniel Bennett, the editor of BBC Science Focus magazine. And in this episode, I'm joined by one of the world's leading forensic anthropologists, Baroness Sue Black. Sue's expertise stretches in many directions. But primarily, her work is focused on using scientific insight to identify the dead and occasionally the living in criminal investigations. Sue's been involved in several high priorities. profile cases over her career, and she's helped the UN identify victims and perpetrators of

conflicts around the world. These days, her work has led her to helping the police track down criminals online, and most recently, she's been recognised for her contribution to science with an appointment to the House of Lords. But before we begin, I'd just like to warn listeners that what follows is a frank and academic discussion about forensic investigation, how it works and what clues a dead body might leave behind, which some listeners may find uncomfortable. If that sounds like you, don't worry. We'll be back next week with an episode about the psychology of curing pain.

In any case, here's what you really need to know about forensic anthropology. For our listeners, you know, when I came to this, I was familiar with the idea of forensics and I was familiar with the idea of anthropology, but I didn't actually know what forensic anthropology is. So what does a forensic anthropologist do? So if I separate it down into its most simple form, which is used the two words, the forensic bit and the anthropology bit,

and hopefully that will bring it together. So the forensic bit is Latin. It comes from the term forensis, which pertains to the forum, and the forum were the courts of Rome. So anything with the term forensic in it means that you're an expert witness to the court. That's all it means.

It doesn't mean you work for the police. It's just you're a word. are a courtroom expert. The anthropology bit is Greek, and that's the study of the human or what remains of the human. So when you put them together, forensic anthropology is the identification of the human or whatever remains of the human for medical legal purposes. So when we go into court, court are particularly interested in who was this individual? How do you know it was this individual and what can you tell from the remains that are left of this individual. So a pathologist will tell you about a manner of death and a cause of death and we'll assist

the pathologist, but we're really about identification. And so to be able to identify, you know, I'm struck by the huge sort of range of skill set. So I suppose it's why it's quite fun. But just to get an idea, so you need to be an anatomist, a geneticist, a even an entomologist, is that a good characterization? People come from different backgrounds. So I came through an anatomy background, and so my whole sort of era is about identification, even from cellular level.

So being able to look under a microscope to say where that tissue has come from, it's liver tissue as opposed to muscle tissue, for example. Others may have come from an archaeological background, so they will understand a lot more about the burying. environment for an individual. Some will come from a genetics. I mean, it can really come from a huge, wide range of expertise. And that's what's really important is that we know within our disciplines in the UK,

who's got the expertise in which particular area. And so we work as almost a national team in that regard, because not everybody has come through the same route. So when you arrive at a scene, then, so you've been called to help identify, identify body or bodies. Where do you start? Because as you said, there's so much, so many tools at your disposal. What's this sort of thought process? Well, it starts with a phone call. And that's why we all hate our phones, is because you never know what the phone call is that's coming in. And usually it will be a police force. And the police will say, for example, a member of the public has been out

walking in woodland and they've found some remains. Can you please come and assist us? So, It could be anywhere. So it could be a 10-minute drive to where you need to get to, or it could be much longer. And that gives you a lot of time in your head to prepare for where you're going and what you're going to do. The most important thing when you arrive at the scene is to speak with the forensic team. So with the officer who's in charge, who will give you what is their forensic strategy, the background to it all, and you'll be briefed either at the scene or it might be at the police station. so they might hold a strategy meeting and everybody will get together. So by the time you get to the cordon,

so that strip of tape at the crime scene, you know as much of the background as you can, that somebody was found earlier this morning by somebody out walking their dog. The police will have set up an outer cordon, and that's to keep everybody out. And to pass that outer cordon, you have to be signed in. And everything about what we do,

do is about recording information, showing what happened, who was there, when they were there, what they did. Once we're through the outer cordon, there will be an inner cordon. And that inner cordon is around the area that is the potential crime scene. Now, it might be a very small area or it might be a very much larger area. And you can only cross into that inner cordon with the permission of the senior investigating officer, the SIO, because it's his crime scene. And he will have, she will have a team there. It's their team, so there'll be a crime scene manager, so it's their sole responsibility to manage that crime scene. Who comes in, who does what, when they leave? They will have photographers there. They will have exhibits officers or productions officers so that

if you find anything, it is bagged and put away. There might have been a pathologist there. There might be an entomologist there. There might be any other forms of ologists, as they call us, that will come into the scene. But they will point to us where they think the body is and they will have identified a pathway or a route that we can take to get to the body because the entire crime scene has the potential to have evidence around it.

And the last thing you want is people tramping all over a crime scene impacting on evidence. So we will have a route in and a root act. The first thing that we will do when we get there is make our decision, is this human? And that sounds as if it's a really sort of obvious thing, but it isn't. If you can imagine all you have are some bones and the bones are scattered, then sometimes it can be quite challenging for a member of the public or a police officer

to know whether the bone that's in front of you is animal or human. If we come in and go, it's a dog, then what happens is the entire crime scene gets shot down and of course everybody goes home. And that's great because that means it happened really swiftly. But if in our first analysis we go, yes, that's human, then we'll come back out again and we'll finish our strategy meeting at the cordon that says, okay, we now know it's human. What is our approach going to be? Are we going to, you know, how are we going to lift the body? So is it an intact body? Is it a decomposing body? Is it just down to bones? How are we going to manage the exhibits as we lift them? What are we then going to do about the undergrowth around it? Is it? that going to be searched? All of these strategies have to be put in place before you've even got in your mind what kind of a body it is that you're dealing with. So your first thought about preservation, I suppose. Preservation. Because once you interrupt a scene, you can never

return it to where it was. So you always want to do the minimum amount of damage and the maximum amount of planning. Something will go wrong. Of course it does. It always does, but you want to minimize that. And everything you do is photographed and recorded so that you can always go back to it to say, what did I do, when did I do it, what did I miss, those kind of things. And it may well be once we've lifted all the remains and they've headed off to the mortuary, then it's about digging down below the body, sifting through the soil, collecting the soil, because you might want to be able to analyze that back at the laboratory, going through the undergrowth looking, is there clothing? Is there any evidence of a wallet, whatever it may be that will help with identity?

The biggest challenge for us is that when you're lifting the bones, for example, in our mind, we're starting to form a profile of the individual. So we're able to say, I think it's female, and I think it's going to be somewhere between about 20 and 30 years of age. And we're doing that as we're going along. And it's very difficult to keep your mouth shut. And you have to, because everything you say, the police will take that as evidence. And so they'll run down a route that says, okay, we've got a female. And we want to make sure we have. And the only way we can do that is then when we go to the mortuary and we spend time with the remains. So we form it in our head what we think we've got, but we try not to be very definitive at the crime scene,

because that detail comes in the mortuary. Once you're at the scene, once you get to the mortuary, is the bone, typically if there are bones to examine, where you start, is that the loudest signal, I suppose, or the easiest place to begin? So our, our, our, our, our, MO is always, the body has to be laid out. So as we're, as we're picking up the bones, we have a little checklist. that says, okay, I've got a right femur, I've got a left femur, I've got a left big toe, where's the right big toe? And so by the time we've lifted everything we can see, we have an inventory of what's missing. Now, if a body is left out in the external environment to decompose, it's exposed to predators. So you'll get foxes, you'll get badgers,

you'll get dogs that will come in and they'll take away bits of the body. But we know which bits are most likely to be taken away, and they'll be taken away. are usually fingers, to be honest. So they stick out the bottom of sleeves. Feet are usually in shoes, so they're protected. Heads are really heavy, but hands are something that a fox can run in, can pick up and we'll take away in cash.

So that we know by the time we've lifted the body of what's missing, and we'll say, okay, we're still looking for a left hand. So we'll start looking for animal trails, and foxes and badgers and things have a real routine pathway. and we'll start to move down the pathway of the animals to see if we can find the bits of hand that are missing. Once we're in the mortuary, our job is we lay the body out in its anatomical position, and that will hopefully confirm to us that everything we thought we found at the crime scene is in fact there and that left hand is still missing. But we'll be able to look at the,

at the ends, for example, of the bones and the forearm to say, are there any evidence of toothmarks? because if there's tooth marks there, chances are that's going to tell us this is a fox, this is a badger, this is going to be a dog or whatever. And it is about hopefully we want to be able to have as much of the body as we possibly can, but we accept that at times it will be incomplete. So we lay it out and we know it's definitely human and we've got everything that we can possibly want. And then there are four features that we use to identify people, big sort of pigeonholes. So are you male or female?

And of course, that one would expect as binary, but of course it isn't at all. And we're not looking at whether you're male or female. What we're looking at is whether your skeleton has got a feminine form or a masculine form. And a masculine form doesn't mean you're male. It may mean you're more likely to be, but you may have been a female who is transgendering, for example. So there's a huge amount of circulating testosterone in your system.

and the skeleton will respond to that. So we have a feminine or a masculine form to the skeleton. And the police will often assume that's going to be male or female, but that can cause problems. Then we will determine how old was the person when they died. Not how long have they been there, but how old were they when they died? Are we looking at someone who's a child? Are we looking at somebody who's a young adult?

Are we looking at someone who's an elderly adult? Once we've done that, we will look at how tall were they? and we'll do that mainly by measuring the bones of their lower limbs. So we'll say, okay, we've got a male. He's between 5 foot 6 and 5 foot 8 in height, and he was 25 to 35 years of age. And the last thing we'll look at is an ethnic or an ancestral association. Now that's really tricky, really, really tricky,

because most of our racial characteristics are in our face. and if we don't have a skull, then we can't do it. And so the police are really looking for you. Am I looking for someone who's Caucasian, which doesn't mean white? Am I looking for someone whose ancestral origin might be sub-Saharan Africa? But of course, in our modern world, we have so much integration of different groups that actually that's really difficult to tell the police with any confidence. So that they want sex, age, ethnic origin and height.

And we can do sex, age and height really well. We really don't want to talk about a possible ancestral origin because it's just fraught with so many problems. And then they'll say, right, what have we got in there that might be identifiable about this young man? Has he had dental work done? In which case, if there is, then we'll pull in somebody called a forensic odontologist, so a forensic dentist.

And they will chart that dental formula perfectly. and that may then allow at future time when we think we've got an identity for the individual to check with our dentists because we have no central record of dental work. Right. I've often wanted because it's such a, it's in such in the public consciousness, isn't it? Check the dental records. Yeah, that's fine. You can only check it when you've got something to check it with. So there's not, there is not some library somewhere that has everyone's x-rays. And often what you'll find as a dentist will only record the work that they have done

because that's all government requires them to do. So if you go to a new dentist, they might not chart all the work that somebody else has done. Their records may only include the work that they've done, so they're incomplete. I see. So you might have a potential name of a person or a person in mind that you're identifying. And it's only at that point you can use the dental records to confirm because you can actually check. Exactly. And it's the same with medical records.

So, for example, if I've got a hip replacement or a knee replacement, then it may well, if it's been done certainly in the UK and certainly in the Western world, there may well be an identification number on that implant. And so there are some registers we can go and check for implant numbers. But if you have gone abroad to have your knee replaced because it's cheaper, then sometimes you'll find those registers don't exist. and some companies won't put unique numbers on each of the implant. So you might have 100 implants with the same number.

So sometimes it's useful, sometimes it isn't. So we want to get to medical records and we want to get to dental records. If we're at bone, of course, we're not going to have fingerprints, so there's nothing we can do with fingerprints, but we will take samples of bone that can be sent away for DNA. And we'll take it from areas that are well protected in the body. So it might be that we'll extract a tooth after the odontologist has been there. It might be that we'll extract perhaps a little sort of segment of the shaft of a thigh bone, for example.

And that can go away to the laboratories to have DNA extracted so that if we get to a name, then we'll be able to check on DNA. We do have a DNA register of individuals who have been convicted of crimes. So we will check whether somebody is on the National DNA Register. But if you've never been sampled and found guilty of a crime, then we don't have a means to find your DNA. So that brings me quite nice to another question I had in terms of things that we understand, I guess, in kind of popular culture about identifying the dead. And that's fingerprints.

Do we still use them in the way that? I suppose we think about them in the public consciousness. One thing that I've picked up on you writing about before is, you know, the idea that a fingerprint is unique. Is that the case? And how useful are they to you? So most scientists have a real problem with the word unique because it is very definitive.

It means you can't be a little bit unique. It's like you can't be a little bit pregnant. You know, you're either unique or you're not. and when it comes to any form of identification, it is a statistical probability. So they say that's why they convey the match and it's a one in a million or a one in a billion is because we cannot say that they are unique because we would have had to test it against every single fingerprint that there is or ever has been in the world. But what we know is that the fingerprint is different on every finger.

It's different across both of your hands. and if you're an identical twin, they're different between those twins. So that gives a confidence that there is such a high level of variation in that fingerprint that we can attest to a high probability that this fingerprint belongs to this individual. But with these things, you have to have something to compare it with. So an isolated fingerprint doesn't tell you that it was a man who was in his 40s that walked or the limp, it just doesn't. All you can do is run that fingerprint and see if it's in a database that you hold. If it isn't, then that fingerprint is of no value to you until you can find

somebody to compare it with. And it was interesting because what was, I thought was incredible, was there was a story that I hadn't heard of Shirley McKee, who's, in fact, it kind of changed how we use fingerprints in criminal cases. Can you just tell, Tell us about that. Shirley McKee was a police officer in Scotland, and there was a murder occurred of an elderly lady, and there was a fingerprint in blood on the door jam at the crime scene. Every police officer and every forensic expert,

we have our DNA samples taken and we have our fingerprints taken so that we can be excluded from the crime scene, so that if there is unfortunate contamination, we can say the reason my fingerprint was there is because I was there and that's why they found it. When they ran the fingerprint in blood, what it did was it flagged up. It was a match for Shirley McKee. Shirley was approached and she said, I'm sorry, but I was not at that crime scene because I was not on duty that day. It wasn't me. And that, of course, set off a huge area of investigation. Do we have a police officer here who's telling a lie that in fact she was there. Now, if she wasn't there on official business, why was she

there? So, in fact, is she a suspect for the murder? Now, very fortunately for Shirley in some ways, but what a horrendous situation is our father was a senior police officer. And so he took it on as a campaign to ensure that he could prove his daughter's innocence. And she went through the most awful, as you can imagine, situation. She was, you know, suspended. And she was, you know, suspended from her job, she'd been accused of perjury in court that she was lying. And what he did was he went away and he found experts around the world and said, talk to me about the way in which we analyze fingerprints. And by and large, it's remember that game you played as a child where you get two photographs

and you have to spot the difference between them, yeah? Fingerprint on a very basic level is about spot the difference. So where are the differences and where are the similarities? And the methodology that had been used up to that point said, if you have 12 points of similarity, then what you've got as a match. Now, of course, if you'd gone to 15 points of similarity, there might have been three that didn't match. And that was what we had with Shirley McKee.

She had 12 points that matched, but she had a huge number of other points that didn't. And so the methodology was what placed her in this difficult position, not essentially the evidence. And that completely changed the way in which fingerprint evidence was then processed from that point forward. We realized that actually we had to be much more detailed about the comparison than we had been in the past. And of course, it opens up that whole question of if somebody has been convicted of a crime and convicted on the basis of fingerprint evidence and nothing else, then those cases need to be re-examined. And I suspect there were a number of cases that were reopened as a result of that.

So I just want to bring things back then, back to the, I suppose, the identification process. And we talked about identifying factors, things like dental work or hip replacements, like that. So those mostly rely on the bones. I just wanted to get a flavor, a sense of what other tools you have at your disposal to kind of help you identify or build a more, I suppose, get a higher resolution picture of the person that you're trying to identify. Everything starts back at that crime scene. So the forensic anthropologist is just a part of a team. And there are other members of the team doing their own thing so that you will have. have environmental profilers who are looking at what pollen is present on the body. Does that tell

you that the person died where they were found? Because if you find in the nasal passages, for example, pollen associated with a particular type of tree, and that tree doesn't exist in the woodland in which the person has been found, then their last breaths were taken somewhere else. So that expert is telling you the body has been moved. And for us, that's important evidence. The entomologist who is there to study the bugs and largely the bugs are telling you about how long has that person been there because of the cycle and the waves of bugs as they come in. That becomes important because that tells us if the body's been decomposing for six months, what will I expect to find? You know, am I looking for soft tissue as well as bone tissue?

The entomologist will look at the bugs and look at the composition of them. to say, is there any chemical found within the larvae that they've taken from the body that perhaps is an indication of drug or otherwise? So there's a whole team working on it and we're just a very, very small part. Sometimes it's about bone. Sometimes it's also about soft tissue. Other times it may be about the bugs. It may be about the pollen. It may be about the soil and the the turn-ups of their trousers. Who knows? Every crime scene is different,

and you react and you modify to that crime scene as the information develops. So I was wondering when I was sort of looking into this, what would you say has been the most transformative kind of technology that's sort of helped you in identification in sort of the last few decades? Because it's interesting because when we talk about DNA, I suppose you would imagine, oh, DNA profiling, great, we can get DNA. But unless we have something to compare it to, it doesn't really give you much. So I was wondering from your perspective, what's been some of the science that's kind of really helped you to be able to identify people better? It is DNA.

Is it? Okay. DNA. So, you know, when Alec Jeffries had that eureka moment in his laboratory in Leicester, when he couldn't get his medical genetics research project to work, and Alec, the most lovely and humble man, so I can imagine I'm scratching his head in the lab, thinking, why doesn't this work? And he had that moment that said it doesn't work because everybody's DNA is different. And that only happened in the 1980s. So, you know, The whole concept of forensic evolving around DNA, for me, given my age, is a relatively recent thing.

And what that's done for us as forensic anthropologists is shifted the type of cases that we do. There's a huge list of missing persons. And, you know, there are a lot of people go missing in the UK and around the world every year. When somebody goes missing, we will take DNA samples from mum and dads. sisters and brothers, or we'll take DNA samples from the room of the person who's missing. It might be that there's dirty underwear in the laundry basket, or there's a toothbrush, or something we can extract their DNA from. And we'll hold that DNA because they're a missing person. When we then find a body and we run DNA through, it goes through our crime database,

but it also goes through the database of missing persons. And then you get a hit that says, okay, unfortunately, this is Joe Blonks. Now that stops the work that I need to do on that case, because now they've been identified. So the forensic anthropology has gone from what were before the 1980s, almost all cases associated with identification, now to the really challenging ones that DNA can't resolve swiftly. So we do try to get the DNA samples out there as quickly as we possibly can. And that, I think, has focused the type of work that we do. So it's made a huge difference, absolutely huge.

And so I wonder, obviously, you have your databases. And this is a sort of, I suppose, a forward-looking question. Is, do you think there, so there's obviously, there's a very high-profile case in the US, the golden state killer, who, who was, if, effectively, they were able to close in on his identity because they had a DNA sample, and they were able to compare that to some ancestry type DNA tests that his distant, you know, third, fourth, fifth cousins and did. So you talked about those two databases. You have the sort of criminal database, and you have the people who have been prosecuted, and you have the missing persons.

Do you anticipate the kind of databases that the likes of 23 and me and and all of those companies have becoming open for these sorts of cases? So that becomes a really interesting ethics and moral question. It's about saying that balance between the right to privacy, the right to give permission for other people to access your data. and some people are very open about it. It's about saying, well, I've got nothing to hide. I wouldn't mind having my DNA held on a DNA database.

But there are other people who feel equally strongly in the opposite direction. So there is no intention that I'm aware of in the UK for us to ever set up a national DNA database where everybody has to have their DNA there. But some countries are going down that route. And certainly when you look at the big ID project, that's going on in India, then that is about taking samples of DNA and fingerprints and so many other things. There is an argument in there, both sides, one side that says if you have nothing to hide, then you're not going to come up on the DNA database, are you, unless you're the dead body?

And there are those who say, I don't quite trust the science or the scientists or whoever it is that holds the database that they're going to do what they say they do and they will not want to be involved in it. So it's a really tricky one. When it comes to these ancestry databases, my personal viewers, and I would never ever send my DNA to one anyway. To me, that just screams madness,

is that I would have given my DNA, which I wouldn't, for a particular purpose, for me to find something out about me, I had not given my permission for investigative forces or agencies to use that data for different purposes. So I have a sort of moral conflict in using those. Now, I accept, and the police rhetoric for it would be, but if we hadn't had that, we wouldn't have caught him, and somebody else may have lost their life as a result, I absolutely get it. But it's one of these thorny issues that really is a balancing act between one.

one side and the other. And by and large, we get things right. But when you're looking at DNA samples that are perhaps degraded, they're not of the best quality. Then I do think we have to be very, very careful when we come forward with what we believe to be DNA evidence, when it's based on however many generational changes we've had, perhaps not a sample that is of pristine condition. And we don't always know that the person who submits their DNA to an ancestry group is who they say they are. That was Sue Black there, revealing how a forensic anthropologist goes about identifying the dead. If you do want to hear more from Sue and I digging a little deeper into her work and discussing how she's helping investigators break up online paedophorees.

Do check out Instant Genius Extra. a podcast available via subscription on Apple's podcast app. And of course, if you want to discover more about the work of a forensic anthropologist, you should seek out Sue's latest book, written in bone, hidden stories in what we leave behind, which is on sale now in all good bookshops. Thank you for listening. The Instant Genius podcast is brought to you by the team behind BBC Science Focus magazine, which can find on sale in supermarkets and news agents,

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