Chewed Gum DNA Cracks Two 1980s Washington Cold Case Murders
The chewed gum DNA case that finally closed two of Washington’s most notorious cold-case murders ended this month with a sentence of 50 years to life for 74-year-old Mitchell Gaff, who pleaded guilty in a Snohomish County courtroom to the 1980 murder of Susan Vesey and the 1984 murder of Judith “Judy” Weaver.
Both women were killed in Everett, Washington, decades apart. Detectives say they caught Gaff only because he accepted a free sample from people he believed were gum-company researchers — undercover detectives running a ruse to collect his discarded gum and extract his DNA from it.
How the Gum Trick Worked
Cold-case detectives reopened Judy Weaver’s 1984 murder in 2020, when improved DNA technology produced a new profile from preserved evidence. The profile matched Mitchell Gaff, a registered sex offender with a violent criminal history, through the federal CODIS database in late 2023.
To confirm the match without tipping him off, detectives approached Gaff posing as researchers conducting a gum “taste test.” He accepted free samples, and investigators collected the chewed gum, extracted his DNA, and matched it to the evidence from Weaver’s case. He was arrested in May 2024 and charged with her murder.
A Widower’s Call Cracked the Second Case
While detectives were preparing for trial in the Weaver case, Ken Vesey contacted the Everett Police Department about his wife’s unsolved 1980 murder. He had lived under a cloud of suspicion for more than 40 years, and he told detectives nothing had ever been resolved after his 21-year-old wife Susan was found sexually assaulted and strangled in their apartment in July 1980.
Detective Susan Logothetti pulled the file and spotted what she believed was the same killer’s signature. A DNA comparison came back linking Gaff to the Vesey crime scene, and he was charged with her murder in March 2025. Faced with the forensic evidence, Gaff pleaded guilty to both murders rather than stand trial.
Justice Four Decades Late
At his sentencing, Gaff addressed the victims’ families in court, blaming his violent past on drugs and alcohol and saying no one had done anything to deserve what he did. The judge imposed 50 years to life, effectively guaranteeing he will die in prison.
Gaff’s criminal history also includes the rapes of two teenage sisters in Everett in 1984, and a violent 1979 home attack on Jacqueline O’Brien, a former law enforcement officer who later helped investigators identify him.
For the families who waited more than 40 years, the court’s decision closed cases that had haunted Everett for generations — solved, at the end, by a piece of discarded chewing gum.
Source: CBS News