Thirty-six years after a teenager’s body was found in the river, her killer is identified

Decades after the brutal murder of a northwest Washington teenager left investigators baffled, modern forensic tests have helped identify her killer.

Tracy Whitney’s body was found by a fisherman in the Puyallup River near the town of Sumner on August 28, 1988. She was naked, and the subsequent autopsy that confirmed Whitney’s name also revealed that her cause of death was asphyxia by strangulation and likely asphyxia. She was believed to have been sexually assaulted, which is supported by additional autopsy findings, according to the Pierce County Sheriff’s Department, which operates in the Tacoma area and is investigating Whitney’s case.

Whitney was 18 when she died. At the time, Pierce County investigators were trying to find clues as they searched for the person responsible for her murder. They interviewed people who knew Whitney and people who dated her when the investigation began. But despite taking DNA samples from the body believed to belong to the killer, investigators were unable to find a suspect.

The case remained unsolved for years. In 2005, another attempt to find the suspect proved to be by running those DNA samples through CODIS – a national database that law enforcement agencies can use to link forensic profiles to crimes and suspects, called the Combined DNA Index System – ultimately unsuccessful as no matches were found to the Pierce County Sheriff.

It wasn’t until 2022 that a Pierce County sheriff’s detective submitted the DNA to a genetic genealogy lab for re-examination, thanks to a grant from the Washington State Attorney General’s Office. Genetic genealogy is a process in which forensic analysts create a family tree from a DNA profile, which in this case allowed law enforcement to identify Whitney’s killer based on a family member.

Findings from the genealogy lab led investigators to the biological son of their suspect in Whitney’s death, John Guillot Jr., and confirmed that the elder Guillot was indeed a DNA match, according to the Pierce County sheriff. Guillot, the suspect, died of cancer in January 2022, just eight months before the lab returned the DNA match implicating him in the murder.

“There were no connections between Tracy and Guillot Jr. and investigators believe this was a case of kidnapping, rape and murder by a stranger,” the Pierce County Sheriff’s Office said in a social media post Saturday post announcing that Whitney’s case was solved. “Our Cold Case Unit always looks to the past and tries to find answers for families like Tracy’s. We are glad that by solving this case they can finally find an answer and closure.”

Although Whitney’s killer has not been prosecuted, her relatives told CBS News affiliate KIRO that knowing he has been identified gives them some sense of peace. Her sister, Robin Whitney, said she hopes publicly identifying Guillot will help solve other unsolved cases because she believes he may have committed several crimes throughout his life.

“We believe John Guillot Jr. likely committed other crimes,” Robin Whitney said in a social media post, according to KIRO. “However, since he is deceased and current legal restrictions prevent his DNA from being uploaded to CODIS (Law Enforcement DNA Database), we hope this policy can be re-evaluated as it may help solve additional cases.”