" " An all-white kitty like this one, called Snowball, unwittingly helped pinpoint a murderer. Madina Gajimuradova /EyeEm/Getty Images

Snowball was owned by a Canadian couple living on Prince Edward Island, Canada. In 1994, their son, Douglas Beamish, was living with them after being paroled from prison. During this time, the Royal Canadian Mounted Police (RCMP) found the body of Beamish's estranged common-law wife, Shirley Duguay, in a shallow grave. Beamish became the prime suspect in her murder. The only problem? The RCMP had no evidence [source: Encyclopedia].

But police did find a leather jacket near the crime scene splattered with Duguay's blood. And some of Beamish's friends said they thought he owned such a coat. Close examination of the jacket uncovered 27 white cat hairs inside the lining. If they belonged to Snowball, that would provide a clear link to Beamish. But forensic scientists couldn't determine which cat the hairs came from. So, they contacted a U.S. lab to see if the hairs could be tested for DNA – something not previously done with animals.

The cat hair did match a blood sample from Snowball. But to prove to the jury that other cats on the island didn't have the same DNA, experts tested 20 others. They all had DNA that greatly varied from that of Snowball's. The result: a second-degree murder conviction and 15-year prison sentence for Douglas. In addition, Snowball's case inspired others around the globe to look to pet fur for clues in criminal cases [source: Boyle].