Murder used to be so simple. Find a victim, do the deed, run away. Even disposing of the body was not so difficult. But then the scientists came along, and suddenly it was it was much harder to get away with it. Catching History’s Criminals: the forensics story (18 June) looked at various murders from the past and showed how the developing techniques of forensic science were used to nail the culprits. The presenter Gabriel Weston describes herself as “a surgeon and writer”, and very good she is too. She speaks convin­cingly to camera and looks authoritative when required to fiddle about with a test tube or a flask. Her tone is informative without being either squeamish or unduly graphic.The first murder she examined took place at Harvard Medical School in the United