SNOHOMISH COUNTY, Wash. — A suspect in the killing of 17-year-old Michelle Koski in 1990 was identified through the use of forensic genealogy, according to the Snohomish County Sheriff's Office.
Snohomish County Sheriff's Cold Case Detective David Heitzman said Parabon NanoLabs used genetic genealogy to help identify Robert A. Brooks, who died in 2016, as the suspect in the sexual assault and murder of Koski.
Koski's body was found on August 25, 1990, by a woman walking her dog at Highway 522 and Echo Lake Road in Snohomish. Koski was last seen near her house in Seattle several days before her body was found.
“After more than 30 years of searching for answers following this terrible murder, we can finally provide Michelle’s family with some answers,” said Snohomish County Sheriff Adam Fortney.
Heitzman said over the last decades, investigators methodically ruled out a long list of suspects using DNA.
Parabon was able to match DNA collected at the crime scene with a distant relative of Brooks who had uploaded their genealogy to Family Tree DNA and GEDmatch, a public genetic genealogy website.
Genealogist Deb Stone, from Kin Forensics, worked for a year building family trees which ultimately led to the identification of two brothers, according to the Snohomish County Sheriff's Office.
The Snohomish County and King County Medical Examiner’s Offices and the Washington State Patrol Crime Lab tested a blood sample from Brooks that positively matched the DNA profile from the crime scene evidence.