Suspect Identities: A History of Fingerprinting and Criminal Identification

"Yes. This, for me, completes the circle—although things have moved on a bit since 2001, when this was published. It’s a more academic book—I mean, it’s very readable, it’s not an academic treatise, but I guess unless you’re really interested then you might think it a bit dry. But he’s a very good writer and he has good sources. What he asks is: how did we get to this idea that we can identify people? Where did it come from, how do we do it, and does it work? That’s the short of it. We need to identify people because if you’re going to put somebody in prison, or even accuse them of a crime, we need to be confident it is the right person. So it’s a really important aspect of criminal justice. Most people don’t realise that, actually, most fingerprint identification is simply used to confirm the identify an offender when they are arrested. “The idea caught everyone’s imagination: that you can measure the body, and that can be used to identify a person” What Cole does, is he goes right back to Bertillon. Bertillon was the French anthropometrist who believed you could identify a person by measuring the body; he took photographs and he would measure noses, eye distances, all that—early ‘facial recognition’ stuff. But this was completely impractical. You couldn’t store this stuff and identify people quickly enough. So it was quite quickly supplanted by fingerprints, because they were left at crime scenes. Not many criminals leave photographs at crime scenes, or at least not before CCTV! But the idea caught everyone’s imagination: that you can measure the body, and that can be used to identify a person. So Cole goes through Bertillon, and some other quite scary people like Lombardo, who would say that ‘the shape of the skull tells you that this person is a criminal’—all this eugenics stuff. Along come fingerprints, and there are eugenicists involved in that as well. Francis Galton, Darwin’s cousin, was a huge eugenicist, he believed in a criminal ‘type’. If you go back to the time of The Killer of Little Shepherds , or a little earlier, this was a time when you got these huge movements of population, immigrants moving from the countryside to the cities. There was more crime, and they wanted to identify criminals. Everything was getting organised, systematised—all these policing organisations were being developed. So Cole goes over the history of all this, and dissects the connections between this and the emerging belief in uniqueness—that your face is unique, for example. But even if your face is unique, in modern facial recognition the measurement of your face requires a machine, and a machine is created by a human, and inside the machine is an algorithm written by a human, and its output is interpreted by a human. None of these things are perfect. They’re all subject to error. But uniqueness was just such an enormously convenient idea. So what happened—in the 1930s, in Scotland, and there was a kind of parallel evolution elsewhere—it was asserted that fingerprints were unique, and are therefore infallible. Actually, that doesn’t logically follow. There was a legal judgement in the thirties in Scotland where the judge said, ‘well, you know, I don’t like you saying these things are infallible, because nothing is infallible.’ He should just have stopped there, but he went on to say, ‘but I guess they’re practically infallible…’ No! Science doesn’t deal with uniqueness. That’s not a scientific question. To establish uniqueness in any real way, you would have to measure everything. The second thing is, you don’t need it. I mean, I’ve gathered evidence, I’ve given really important evidence in many criminal trials which was nothing like unique. It was highly arguable. But it was on point, it went to the heart of the case: did this happen, or did that happen? Was this person there? Or was someone else there? The courts don’t need uniqueness, they never have. But it’s enormously convenient. “The Shirley McKie case opened up this whole argument over the uniqueness of fingerprints” Cole exposes all this really quite well. There’s a little vignette in my book, where I describe meeting a fingerprint expert at the Old Bailey, and he spends all his time telling me how unimportant my evidence is, and how important his evidence is—because it’s conclusive. Which is just another word for ‘unique’. I was quite young and thought, well, surely they wouldn’t call me to court if my evidence was of no relevance. The courts are quite busy; they only call witnesses that have something to say. When I went back to the lab, I told my colleagues and they all just burst out laughing. They said, ‘He’s one of the mad fingerprint people who think they’ve got the answer to everything.’ It’s just dogma, it’s just faith. No science in it at all. Why is this significant? Well, have you heard of Shirley McKie? Or Brandon Mayfield. These are the two big cases. Shirley McKie was a Scottish police officer who was accused of leaving a fingerprint at a scene. She didn’t, she was never at the scene. It was a mistake by the fingerprint experts. The debate was a huge problem, went on for more than a decade, and eventually the Scottish Government paid out more than £750,000 to Shirley McKie. That opened up this whole argument over the uniqueness of fingerprints, and error, accuracy, faith and dogma and exposed the whole thing. The Brandon Mayfield case had some very interesting background factors—he was a US citizen and a Muslim, which I’m convinced had a bearing. The Madrid Bombing of 2006 was a horrific bombing that killed well over 100 people. The Spanish government’s criminal justice authority sent out all these fingerprints that they found associated with the crime. One went to the FBI, and they identified this American Muslim lawyer called Brandon Mayfield. “Nine times out of ten, eight times out of ten, the forensic evidence is useful but not critical” The Spanish experts eventually say, ‘we think the fingerprint is from another guy, who happens to be an Islamic terrorist.’ But the FBI says, ‘no, no, no. You’ve got it all wrong. It’s this guy—Brandon Mayfield.’ Eventually they have to admit they’ve made a complete error, they’re absolutely wrong. There goes the infallibility of fingerprints. They have to pay out $2 million for making an unfounded accusation. There’s a huge fuss about it, all around the world—as Paul Simon had called it, many years ago—the myth of fingerprints. The bubble had burst. Since then, the whole business of fingerprints has been cooling. There’s been an enormous transformation from this dogmatic belief, to what it should be: fingerprints are a perfectly good way of identifying people, but you need to be honest. Sometimes errors are made, and you need to pay attention to certain kinds of cases which are problematic. Almost all the misidentified fingerprint cases involve difficult fingerprints to deal with. They’re slightly distorted, things like that. They require a very careful procedure to make sure you’re not biased. What happened in the Mayfield and McKie cases was that they made mistakes and then they dug in. So that’s the link back. There’s an element of that. The problem is that forensic science is seen as this monolithic body of knowledge, and it isn’t. What is? So the first question you should ask is, what kind of forensic science is involved? If you say DNA, most DNA profiling is pretty safe stuff. Not perfect, but pretty safe. This is amongst the best evidence that you will get in a court case. But that’s only a certain type of DNA. All the new science that’s coming out, you have to treat it with caution, as you say. You have to be careful. DNA mixtures, which are very common in sexual offences, are much more complicated and require much more caution, like the distorted fingerprints. So you should never just believe this stuff, nor should you automatically disbelieve it. You should ask fairly seriously questions about the science—and here’s the thing—and the person (the expert witness) who’s telling you the story. Because some people have credible credentials, and other people haven’t. Even the people with credible credentials sometimes make mistakes. So you have to unpack it: Why do you believe this? Why do you believe that? That’s what should happen in a good court case. Although things only seem to go wrong in forensic science when the evidence is really important. Then, because then everybody digs in, there is a really deep argument. But nine times out of ten, eight times out of ten, the forensic evidence is useful but not critical. You know: you get a DNA match from a crime scene, it leads you to an offender, then you establish that there are a couple of witnesses that link the offender to the crime scene and he drives the same kind of car. You’ve got a partial numberplate. Then, the DNA evidence is what I would call ‘investigative evidence’: it takes you to someone. It’s not the case against them, it’s only part of the story. So: caution, yes. Honest scepticism is what you need in all these instances, and that’s something that can be missing quite a lot of the time."