CALL THE grime SQUAD

It’s a dirty business, murder, as crime fiction queen Val McDermid knows all too well. Now she turns from fiction to fact to reveal the grim business of forensics

Nowadays, virtually every TV drama contains a scene in the pathologist’s lab, with bronzed actors in surgical uniform poking around at a corpse on a slab. This must surely mean that any actress who can hold her breath for a long time without blinking and have her body poked without giggling is assured of a job.

The time is long gone when a detective could solve a crime with a beady eye, a raised eyebrow, a puff on a pipe and a well-timed question. Instead, he is more like a removals man, cordoning off the scene of the crime before bundling everything into plastic bags, ready for the forensics team to take over.

Crime writers have also been obliged to make the move away from the sitting room and into the lab. The modern Miss Marple has had to exchange her wicker basket for a microscope and her bonnet for a surgical mask.

Val McDermid has long embraced the world of forensics. In this new book, she has moved from fiction to fact, with straightforward chapters on entomology, pathology, toxicology and so forth, full of famous case histories and interviews with experts in their fields.

Some of these experts are fascinating figures. I was particularly taken with Dr Martin Hall, head of research at the Department of Entomology at London’s Natural History Museum. He helps curate 30 million insect specimens but, says McDermid, ‘at any time his mobile phone might ping with a police request to drop everything and rush to a crime scene’.

Dr Hall shows McDermid some of the experiments he is conducting. ‘It’s a world where familiar objects have quite different meanings,’ writes McDermid. ‘Carry-on suitcases are home to pigs’ heads, in order to explore which flies manage to lay their eggs through the gaps in the zips. Dogs’ cages hold rotting piglets. Tupperware boxes are filled with preserved maggots.’

If you find it offputting, then this may not be the book for you. On virtually every page, there are body parts wrapped in newspapers, heads stuffed into biscuit tins or rotting hands with their fingertips cut off. ‘The first thing a pathologist does when examining a corpse is to take its rectal temperature’ is a fairly characteristic start to a paragraph. McDermid is not one to shy away from what happens next: the swabbing of the sex organs, the cutting of the body in a Y shape from shoulders to groin, the removal of organs and so on. Descriptions of the comings and goings of insects are barely less grisly. ‘In the height of summer, a typical blowfly egg will take 15 days to become a fly. After one day the egg hatches into a maggot, which shreds and rakes in decaying flesh with the two hooks on its mouth. Because its eating and breathing organs are at opposite ends of its body, it can eat and breathe simultaneously 24 hours a day. Over the next four days it eats voraciously and grows to 10 times its original size...’ But for those with strong stomachs, there is plenty to chew on, not least the strange to-ings and fro-ings between the worlds of fact and fiction. The first crime investigation laboratory was set up in 1910 by a Frenchman called Edmond Locard. Locard was an addict of the Sherlock Holmes stories, particularly A Study In Scarlet, in which Holmes says: ‘I have made a special study of cigar ashes – in fact, I have written a monograph upon the subject. I flatter myself that I can distinguish at a glance the ash of any known brand, either of cigar or tobacco.’

Years later, Locard himself published a real paper on identifying tobacco from the ashes at a crime scene, called The Analysis Of Dust

There are body parts wrapped in newspapers, heads stuffed into biscuit tins

Traces. He also wrote one of the most influential phrases in forensic science, the Locard Exchange Principle: ‘Every contact leaves a trace.’

McDermid promises her book will act as ‘a firm reminder that truth is stranger than fiction’. Often the two become intertwined. In her chapter on fire scene investigation, McDermid tells the strange case of a Californian police officer called Captain John Orr, an arson investigator. Over his 20-year career, Orr had instructed more than 1,200 firefighters, had run seminars on fire investigation and had written articles for the American Fire Journal.

In 1991, Orr completed a novel called Points Of Origin, which he described in a letter to a publisher as ‘a fact-based work that follows the pattern of an actual arsonist who has been setting serial fires in California over the past eight years. He has not been identified or apprehended and probably will not be in the near future. As in the real case, the arsonist in my novel is a firefighter.’

The manuscript fell into the hands of police pursuing a serial arsonist responsible for setting fire to 2,000 buildings

over a seven-year period. Sure enough, it turned out that Orr himself was the arsonist and had regularly been in charge of investigating the origins of the fires he himself had started.

McDermid spins her way through many more familiar cases – Jack the Ripper, Harold Shipman, OJ Simpson, the Omagh bombing – but in such a rata-tat-tat form that it is hard to detect much new. On the other hand, those wishing to investigate a crime should pick up a few tips. And so will those wishing to perpetrate one.

I didn’t know, for instance, that if you want to get rid of DNA evidence, you never wash an item on a cold cycle with a non-biological detergent; or that when you switch off a mobile phone, it records the mast with which it last communicated. And, if ever I want to frame someone, I’ll remember to distribute the blood properly and, when distributing glass, to place only a few pieces in their clothing rather than a whole bucketful.

McDermid also mentions quite a few forensic experts who have proved decidedly dodgy. In recent years, Sally Clark was wrongfully convicted of murder after two of her babies in succession died in their cots. Paediatrician Roy Meadow claimed in court they had been shaken to death, saying that the odds of two cot deaths in the same household were ‘73 million to one’. Later, the Royal Statistical Society called this ‘a serious statistical error’ and condemned Meadow for failing to recognise that siblings share very similar genetics and if one is prone to cot death, the other is much more likely to be.

Bernard Spilsbury, an Edwardian pathologist’, regularly suppressed evidence that didn’t tie in with the way he wanted the jury to swing. In fact, it was Arthur Conan Doyle who first suggested that he couldn’t be trusted.

A decade or two from now, will our own faith in DNA be similarly shaken?