After 36 years, police in Washington have identified the killer of an 18-year-old woman.
Through familial DNA, the Pierce County Sheriff's Department identified John Guillot Jr. as the killer of Tracy Whitney. Fishermen in the Puyallup River found Whitney's nude, battered body on Aug. 28, 1988. She had last been seen alive at a local Burger King, according to PEOPLE.
The cold case had frustrated authorities, who interviewed everyone Whitney had known and dated. In 2005, the suspect's DNA was placed into the law enforcement database, CODIS, but no matches were found.
In 2022, police submitted the suspect DNA profile for genetic genealogy testing. Authorities reconstructed the killer's family lines dating all the way back to the 1700s.
Eventually, by constructing the family tree, police were able to hone in on Guillot Jr. Unfortunately, Guillot Jr. died of cancer eight months before the DNA connection was made. Also, Guillot Jr.'s body had been cremated, preventing police from directly comparing the suspect's DNA to Guillot Jr.'s.
Police were able to confirm Guillot Jr. was the killer through a DNA sample from his son. John Guillot III had also died recently, and police obtained a sample from the county medical examiner. The test showed that John Guillot III was the son of the killer.
Police stated that there was no known connection between Guillot Jr. and Whitney. Detectives believe this was a stranger abduction, rape and murder. Thus far, Guillot Jr. has not been connected to any other victims.
"Tracy was a good big sister. She has really been missed throughout my lifetime," Robin Whitney said. "It's been really hard growing up without a sister, but I'm just happy that we've finally found who did this so she can rest peacefully."
