Pet DNA Helps Investigators Take a Bite Out of Crime

They're man's best friend — but they're quickly becoming law enforcement's best friend too.

Now more law enforcement officials are applying forensic methods to cases involving animals.

Beth Wictum, Director of the University of California Davis Veterinary Genetics Lab said there is usually a transfer of biological evidence in the form of saliva, hair, urine or feces from a crime scene to a victim that provides critical evidence.

"People are always amazed to see we are doing this kind of work because animals have DNA just like people do, but it doesn't occur to people that we can do the same type of testing," Wictum said.

Wictum's lab is the largest domestic animal testing site in the world and handles hundreds of cases a year from all over the world. Their findings have lead to the prosecution of several criminals.

In one case, the lab used DNA testing to match dog excrement found on the bottom of a murder suspect's shoe to excrement found near the crime scene — a piece of evidence that helped secure the man's conviction.

In another case, a sexual assault victim couldn't pick her attacker out of a lineup — but she remembered her dog had urinated on the man's pickup truck. The dog's DNA matched DNA traces found on the truck's tire and the suspect pleaded guilty.

Animal DNA also helped link Arizona resident Steven Patton to the 2005 murder of Veronica Ann Youvella, an exotic dancer in Phoenix. Patton, who was later found guilty, wrapped her body in a blanket full of dog hair. Investigators, who arrested Patton less than a month after her body was found, were able to match the fur to Patton's pet.

Maricopa County District Attorney Andrew Thomas said the key evidence was the dog's saliva. "Pets often lick themselves and they were able to take the salivia, and link that back to the defendent's dog. That was powerful evidence."

Wictum said so powerful that it becomes almost indisputable in court.

"Usually we say the chance of a randomly chosen animal having that DNA profile is less than one in a million," Wictum said.

And animal DNA analysis isn't just limited crimes committed on people.

In Richmond, Virginia Marylin Christian had Wictum's lab conduct tests after her beloved cat Cody was found dead under suspicious circumstances two years ago.

Authorities collected saliva from a neighbor's dog, Lucky, to see if it could be genetically linked to hair found in Cody's mouth and claws. The result? A one in 67 million chance the hair belonged to any animal other than Lucky.

Thomas said DNA collected from pets has literally changed the way police do their jobs. "As we've seen in this [Patton] case you can obtain DNA evidence in unpredictable ways and it's better to air on the side of gathering too much evidence you can sample for DNA.

The Associated Press contributed to this report.