Andrew Fitzherbert was convicted and sentenced to life in prison on the basis of DNA evidence alone. His case shows that it is often not the technology or the science but the supervising biologist’s subjective interpretation of the results that is the crucial factor in assessing whether a suspect sample and a crime-scene sample “match.”
by Mary Garden
On Friday, February 27, 1998, between 4 p.m. and 8 p.m., veterinarian Kathleen Marshall (subsequently dubbed the “Catwoman”) was murdered in the downstairs clinic of her home in Wilston, on Brisbane’s northside. Her decomposing body with 52 shallow stab wounds was not discovered until Sunday afternoon when two directors of the Cat Protection Society of Queensland (CPSQ), of which Marshall was president, visited her home. Sixteen cats and three dogs, unfed and distressed, were upstairs.
The police investigation initially focused on members of the CPSQ where power struggles and infighting had been a common occurrence, intensifying during the six months before 52-year-old Marshall’s death. In April, however, Ken Cox, a forensic biologist from the John Tonge Center, announced that he had found male blood in the crime-scene samples. Investigators decided to eliminate every male person involved in the deceased’s life, beginning with male members of the CPSQ and any male connected to a female member.