BOOK REVIEW: Forensics

Crime novelist Val McDermid gets under the skin of forensics – from blowflies and maggots to toxicology and genetic fingerprinting – in this visceral book tie-in with the Wellcome Collection exhibition.

Forensic entomologist Martin Hall and fingerprint expert Catherine Tweedy discuss the challenges they face when presenting evidence in court, though ‘cross-examination can strengthen forensic techniques by putting pressure on them’.

So ‘a trial is the ultimate test of forensic evidence’, writes McDermid, a point reinforced by the combination of microscopic particles of blood and CCTV footage which led to the conviction of Gary Dobson for the murder of Stephen Lawrence.

Sometimes experts make headlines for the wrong reasons. Paediatrician Roy Meadow’s evidence on cot deaths led to the conviction of Sally Clark for the murder of her two babies. Following pathologist Alan Williams’ suggestion that one of the babies died from a bacterial infection her conviction was quashed. And evidence presented by pathologist Spilsbury in the trial of Dr Crippen, who was found guilty of drugging and murdering his wife, has since been called into question by DNA testing. McDermid cites Andrew Rose’s book Lethal Witness and its assertion that ‘Spilsbury caused at least two miscarriages of justice and several more unsafe verdicts’.

McDermid outlines the role of crime scene investigators before a case reaches court, such as when police officer Sharon Beshenivsky died after a shooting in Bradford. Those responsible were convicted thanks to ballistics experts, CCTV footage and witnesses, and the national Automatic Number Plate Recognition system.

A fire scene presents other challenges. Investigator Niamh Nic Daeid, while careful not to cross-contaminate the scene, may have to sift through debris by hand and interview witnesses. Sniffer dogs – whose sense of smell is 200 times more sensitive than a human’s – can help find accelerants like petrol, paraffin and white spirit. Identifying a match brand and ‘petrol branding’, which involves identifying the additives used by manufacturers in petrol, can all provide incriminating evidence of arson.

In a chapter on forensic entomology – the use of insect biology in solving crime – McDermid goes back to the 13th century and looks at a Chinese textbook on forensic medicine – The Washing Away of Wrongs. A fly attracted to minute traces of blood on a money lender’s sickle led to him confessing to murder. In 1935, maggots feeding on decomposing body parts led to police linking them to the disappearance of two women in the Buck Ruxton case.

McDermid enriches her harrowing prose with mind-boggling stats, such as Dr Harold Shipman murdering 210 of his patients and possibly a further 45. This book is a fitting – and generously illustrated – accompaniment to the exhibition.

Nicholas Goodman is a sub-editor at the Law Society Gazette