Your primary line is as a writer of fiction, so this is a bit of a new direction for you. What was your thinking behind writing the book?


I was asked to do it. It’s a companion piece to an exhibition they’re doing at the Wellcome collection next year called ‘From the crime scene to the courtroom’. They wanted a book to sit alongside that – not a catalogue of the exhibition but a book about the current state of forensics and the historical road that’s brought us here.

They came to me and said: “you clearly have an interest in forensic science – would you like to do the book?” and I said no, I'm not a scientist - I just make stuff up. But we talked around it and eventually came up with the format that I would talk to experts in various disciplines and construct the book around that. I have done non-fiction before but that was 20 years ago. In the intervening 20 years I forgot how much hard work it was to write non-fiction – you can’t just make it up when you get stuck. You actually have to back it up with solid information.

That leads on to my next question. How accurately do you think forensic science is represented on TV and in novels?

In books I think it tends to be more accurately represented because we incline more to make the story work in terms of the science, whereas television tends to make the science work in terms of the drama.

I think you have the leeway in a novel to be a bit more elastic with your timeframe. You can say: “it was two weeks later when the test results came back”. You can’t do that in television, so they just make it serve whatever drama they want to tell.

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So there’s room for a bit of manipulation by the author?

Yeah there is, but you don’t just make stuff up. I think one of the interesting things for crime writers in recent years has been the application of science to cold cases. That’s been very interesting for us to work with from a narrative point of view, because you can do things with split narratives. You can do investigations in the terms that they used to be done, before forensics was available, and then you can apply the modern forensics to it. So from that point of view, it’s been a distinct advantage.

You’re quite good friends with [forensic anthropologist] Sue Black. Do you call upon her assistance when you have a forensic question?

Yeah, when it’s something in her area of expertise. Forensic scientists are generally very generous with their time and their expertise, so people will weigh in and help you. I now have a handful of people I can turn to – I phone them up and say: “OK, here’s what I need – how do I make this work?”


Do you ever use forensic techniques as a starting point for your fiction writing?

Yeah, sometimes the technique itself will give you the starting point for an idea. The classic example for me is my book Killing the Shadows, which is about geographic profiling. In the mid-1990s, I happened to meet a guy called Kim Rossmo, who at the time was working in the Vancouver Police Department. He had developed this algorithm which looked at linked crimes and predicted where the killer was likely to live and/or work. When I met Kim, he was beta testing this with a couple of Canadian police departments, and it was having very promising results.

Based on this idea, I wrote a novel that was loosely based on geographic profiling back in 2000, when nobody was really doing that. So sometimes you get a jump-start on the game when somebody tells you about something like that.

Asking the reverse, have you ever, after doing the research, hit upon something and gone “oh no, I did that four books back and I made a mistake”?

No. I’ve made mistakes in my books but not those kinds of mistakes – I check stuff like that. The things that you don’t check are the things that you think you know about, and that’s not the science stuff.

But the science moves on as well. I published a book in 1989 that hinged on something to do with computer science, and people now go: “you had computer programs on cassette tapes? What are cassette tapes?” So things become historical curiosities. That’s one of the reasons you have to put the science in its proper place in the story. The novel can’t be at the service of the technology – the novel always has to be at the service of the story and the characters. Otherwise, when the science moves on, nobody will read the book.

You’ve met a lot of experts, so I was wondering if you think there are any defining characteristics that forensic scientists seem to have?

Well the first obvious one is curiosity – not taking things as you find them, and having a degree of healthy scepticism. But what marks out the people I met was not just a passion for the science, but also for the humanity. Every one of the scientists I met impressed me because they understood that the science is at the service of the living. It’s not just about speaking for the dead – it’s about trying to find justice for the living and giving closure or explanations to people.

Is there anything that stood out in your mind from your visits to labs and forensic departments?

To be honest, I didn’t visit many labs. I’m quite squeamish – I don’t really want to see crime scene photographs and cadavers. But the thing I probably found most fun was the entomology stuff at the Natural History Museum. Martin Hall [Head of Entomology at the NHM] is really passionate about what he does and he just wants to share it all.

He took me up a tower – the turret in the NHM that's almost Harry Potter-like with its spiral stone staircase - where they do experiments. He showed me what were ordinary carry-on suitcases, but inside were pigs' heads because they were trying to see which flies could lay their eggs through the zips. All around you is this bizarre sort of Alice in Wonderland place in the sky with boxes of maggots in different stages of pupation. It was fascinating but I think most people are nauseated by the idea of maggot masses and creepy-crawly things.

It was a very different world, but clearly one that is very important in terms of its scientific application to the investigation of death. Entomology is one thing you can’t argue with: it can tell you exactly how long under certain conditions it will take for a fly to lay its eggs, the eggs to turn into larvae, and for the larvae to pupate. It gives you a time at which the person was no longer alive, which takes you a long way back towards discovering times of death or where the body was kept. You don’t hear much about it, but in many cases it’s quite crucial.

Do you think there will ever come a point with these technologies where it will become very rare for people to get away with crimes?

I think that’s the end point that we’re moving towards, but it will take a while to get there. When science does one thing, the criminals will often learn to do another. For a while, the digital forensics people were ahead of the game because they understood about metadata embedded in images online. But now, many of the criminals understand this and they’re putting their photographs through a process that strips them of metadata before they post them. With every step forward, somebody out there will try and figure their way around it.

It’s one of those things that's become a double-edged sword. With DNA, for example, we can now detect DNA in such small amounts that there are all sorts of circumstances in which your DNA can turn up, even in places where you haven't been. For example, you hug your girlfriend, she goes to work, your DNA is on her jacket, she hangs it up and some of your DNA gets transferred to her colleague’s jacket. Then they’re walking home and get mugged, with your DNA on their jackets.

As we get into these sorts of areas, it becomes increasingly problematic. You have to be very careful that your evidence is of a gold standard. I think this is an area that’s going to come under increased questioning in the next stage of science in the courts.

Val McDermid's book Forensics: The Anatomy of Crime is out now on Profile Books


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James Lloyd
James LloydStaff writer, BBC Science Focus

James is staff writer at BBC Science Focus magazine. He especially enjoys writing about wellbeing and psychology.