The Scottish crime writer Val McDermid is a fan of forensic scientists. She points out they they ‘are willing to engage with the darkest and most frightening aspect of human behaviour on a daily basis’ and make sacrifices for the sake of justice. They appreciate their champion too. McDermid played a crucial role in mobilising other famous crime novelists in support of the ‘Million for a Morgue’ campaign to fund a world-class mortuary at the Dundee University Centre for Anatomy and Human Identification. In exchange for donating, members of the public were allowed to vote for which writer should have the morgue named after them. The genre’s director, the forensic anthropologist Sue Black (one of several living scientists who appear in this book), at whose feet McDermid has been sitting for two decades, announced delightedly that the winner was ‘the fabulous Val McDermid’. Such famous supporters of the appeal as Lee Child and Kathy Reichs came nowhere but in recognition of the strong voting for another Scot, Stuart McBride has a dissecting room named after him.
I’m a crime writer myself, but being squeamish I am from what Reginald Hill christened the Jane Austen wing of the profession. McDermid is made of sterner stuff and take the gruesome in her stride. Having long been fascinated with the methods of discovering who did what nasty thing to whom, she decided to investigate the history and everyday realities of forensic science. Her research led her from the pursuit of maggots at the top of the Natural History Museum to holding somebody’s heart in her hands.
It’s all been time well spent. McDermid uses her novelist’s skill to create a fascinating unfolding narrative of trial and error and brilliance and hubris in a book that takes us rapidly from 13th-century China (Song Ci, author of The Washing Away of Wrongs, recorded how a contemporary coroner identified a murderer because of the flies attracted to the minute traces of blood on his sickle) to 2014 (when a bloodstain a millionth the size of a grain of salt can provide a DNA profile that can identify not only its originator but also the great-grandfather who bludgeoned his girlfriend to death in 1901). Along the way we meet many of the gifted and obsessive people who put science at the service of justice. They include the bloodcurdling toxicologist Mathieu Orfila, who in the early 19th century spent three years testing poisons on several thousand dogs, the appalling suffering of which helped produce the invaluable General System of Toxicology; or, A Treatise on Poisons.
By the end of it, I was almost left feeling sorry for criminals. There’s no longer a level playing field. However smart you think you’ve been, with all the entomologists, pathologists, toxicologists and the rest on your trail, you’re really up against it.
If you’re thinking of murdering your spouse, read McDermid’s book and you’ll reconsider divorce. You could take the elementary precautions we all know about (protective clothing and clever disposal of murder weapons, for example), but you’ll still have to face up to Locard’s Exchange Principle (named after the pioneering investigator Edmond Locard): ‘Every contact leaves a trace.’
Set fire to the scene of the crime? Well, the match with which you started the fire has identifiable powdered rock in its head that survives extremely high temperatures. Bury the corpse under the floorboards and it’ll be found by blowflies, super-sniffers that can lead thousands of their mates through airbricks to feast on a decomposing body. And then there’s the little matter of how physics is brought to bear on the pattern of blood splatters.
However, forensic scientists and those who use their techniques are human too, and McDermid delivery plenty of warnings about jumping to convenient conclusions. For instance, ‘fingerprinting is not a science; it’s a comparison’ and should be treated as ‘opinion evidence’, not fact, since ‘experts run the risk of finding matching minutiae because they are looking for them’. The handsome Bernard Spilsbury, courtroom virtuoso and the first celebrity pathologist, was loved by juries: Dr Crippen was sent to the gallows in 1910 when Spilsbury identified as his missing wife a torso that has recently been shown to be male.
Then there is the problem that public expectations of science have been inflated by television dramas — what is known as the ‘CSI effect’, after the American series CSI: Crime Science Investigation. This has convinced many people that DNA evidence is unchallengeable, even though lab contamination is a very real threat, and — as with fingerprints — experts can find patterns because they’re looking for them.
McDermid discusses plenty of the other tools available to the forensic investigator, including digital analysis, the anthropological identification of bones, facial reconstruction, profiling (or behavioural investigation) and forensic psychology, which helps elicit useful information from victims, witnesses and perpetrators alike.
Not all forensic scientists are up to persuading a jury faced with an aggressive defence barrister seeking to discredit the evidence. But Val McDermid is as robust about this as she is about everything. Scientific discoveries have to be tested not just by your scientific peers, but also brutally in court, ‘the anvil on which scientific evidence is struck’. The people who do this ‘amazing’ work are ‘frankly, awesome’, she concludes rather breathlessly. Well, she’s certainly done them justice.
Profile Books 2014, 310pp, £18.99