Professor Dame Sue Black, a leading forensic scientist, delves into the intricacies of her field and the importance of expert witnesses in her new book, "An Expert Witness." The book explores how forensic science has evolved to make convictions more likely, even in historically challenging cases.
One notable case discussed is the 1912 murder of Marie Latelle in Lyon, France. Suspicion initially fell on her boyfriend, Emile Gourbin, who claimed to have an alibi. However, forensic analysis of scrapings from under Gourbin's fingernails revealed cosmetic components. A local chemist confirmed these matched Latelle's custom makeup, leading to Gourbin's confession. He had manipulated the perception of time and used alcohol to confuse his alibi witnesses.
Black, whose own career spans war crimes investigations in Kosovo and identifying victims of the 2004 Asian tsunami, emphasizes a grounded approach when presenting evidence in court. She describes her practice of removing her shoes to direct her attention to the jury, rather than solely to legal professionals.
This approach contrasts with that of Sir Bernard Spilsbury, a prominent early 20th-century pathologist whose confidence, according to some assessments, may have contributed to miscarriages of justice. Spilsbury famously stated, "I have never claimed to be God, merely his locum on his weekends off."
The book also revisits well-known cases, such as the conviction of Colin Pitchfork, who was found guilty through DNA profiling for a series of rapes and murders in Leicestershire. Pitchfork had attempted to evade detection by having another person provide a blood sample, a deception that was only revealed when the substitute mentioned it to a colleague.
Black's work offers fascinating insights into forensic details, such as the prevalence of arsenic as a poison in the 19th century, earning it the nickname "the inheritance powder." The book also touches on seemingly minor details like the average number of hairs on a blonde versus a redhead's head, the average number of scars on male versus female hands, and the timing of blood spatter in assault cases.
Black is portrayed as a narrator who understands the limits of certainty. She is cautious about overstating conclusions, recounting an instance where her statement that dismemberment tools could be found in a typical kitchen, including her own, led a defense attorney to quip, "Remind me not to take up an invitation to yours for dinner."