DNA readings from cat hairs are not a just a topic for TV-series, but they have once again helped to solve a homicide case, showing the increasing power of pet databases’ to help solve crimes.
All cat owners know that cats shed hair, especially in the spring and summer months when the weather is warmer. Cat fur usually ends up on the floor, on our clothes, or under our shoes. A single strand of cat hair has helped to investigators prosecute culprits in many open cases.
The latest one involves a man in Britain who was convicted of manslaughter after prosecutors found a genetic link between his pet cat, Tinker, and cat hairs found at the crime scene. John Wetton, the University of Leicester geneticist who led the cat DNA project, said in a statement “This is the first time cat DNA has been used in a criminal trial in the UK. We now hope to publish the new built database so it can be used in future crime investigations”. However, it’s not the first time a homicide case has been solved thanks to cat DNA.
In 1994, a Canadian woman named Shirley Duguay was found dead in a shallow grave. A very innovative technique, called “standard short tandem repeat (STR)” has been applied to this homicide and has helped to find the killer. Her estranged husband, Douglas Beamish, had a white cat named Snowball and its hair was found in one of the pocket of a discarded leather jacket, covered with Duguay’s blood — key piece of evidence in the case. The cat’s hair have been analyzed by the Animal Genetics Group, Laboratory of Genomic Diversity of Frederick in Maryland confirming the match to Snowball’s genetic signature, and experts tested about 20 other cats from the area to show that the signature was rare. Thanks to this evidence, Bemis was convicted of second-degree murder and sentenced to 15 years in prison.
A researcher involved in that case, Robert Grahn of the University of California at Davis, said cats might be particularly well-suited for forensic analysis — due to their clingy hairs as well as their habit of licking themselves for grooming. Because cats are such thorough groomers, shed fur can have sufficient genetic material for trace forensic studies. In the US, a designated DNA databases for cats has already been created, and there is the possibility to use those as evidence during a trial. The cat DNA can be collected every time cats are under a chirurgical intervention, vet visits or any other routinary exam. The University of Veterinary Medicine of California has built a database with the DNAs of 26 breeds, totalling 1394 cats. Now, the next frontier of crime solving may be to apply those techniques to other domestic animals such as dogs, in order to build bigger databases.