DNA From Chewing Gum Leads to Arrest of Convicted Serial Rapist in 2 Cold Case Murders

Mitchell Gaff, a diagnosed 'sexual sadist,' now faces trial for the 1980 and 1984 killings of two women in Everett, Washington.

Apr. 15, 2026 at 1:03am

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Mitchell Gaff, a 68-year-old convicted serial rapist, has been charged with the murders of two women in Everett, Washington in the 1980s after DNA collected from chewing gum he discarded during an undercover sting operation matched evidence from the cold case crime scenes. Gaff has a long history of violent sexual crimes, including the brutal rape of two teenage sisters in 1984 while he was on probation for a previous assault.

Why it matters

This case highlights the power of DNA evidence in solving cold cases, even decades later, and the ongoing challenges of the criminal justice system in keeping dangerous repeat offenders off the streets. It also sheds light on the lasting trauma experienced by Gaff's victims and their families.

The details

In May 2024, undercover Everett police detectives posing as gum industry researchers collected DNA samples from Gaff by having him taste test various gum flavors. This DNA matched evidence from the 1984 murder of Judy Weaver and the 1980 murder of Susan Vesey, both of whom were sexually assaulted and strangled in their Everett homes. Gaff had previously been convicted of violently raping two teenage sisters in 1984, just months after assaulting another woman, Jackie O'Brien, in 1979.

  • On July 12, 1980, Susan Vesey was killed in her Everett home.
  • On June 1, 1984, Judy Weaver was killed in her Everett apartment.
  • In May 2024, undercover detectives collected DNA evidence from Gaff using a chewing gum ruse.
  • In March 2026, Gaff was charged with the murders of Vesey and Weaver.
  • Gaff's trial is scheduled to begin in September 2026.

The players

Mitchell Gaff

A 68-year-old convicted serial rapist and diagnosed 'sexual sadist' who is now charged with the murders of two women in Everett, Washington in the 1980s.

Jackie O'Brien

A former Washington State Patrol officer who survived an assault by Gaff in 1979, and is now planning to attend his upcoming murder trial to support the victims' families.

Judy Weaver

A 42-year-old mother of two who was murdered in her Everett apartment in 1984.

Susan Vesey

A 21-year-old woman who was murdered in her Everett home in 1980, leaving behind a 3-month-old baby and 2-year-old daughter.

Everett Police Department

The law enforcement agency that used an undercover 'gum ruse' to collect DNA evidence that linked Gaff to the cold case murders of Weaver and Vesey.

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What they’re saying

“I am so proud of our Everett Police Department for solving this murder case by utilizing advancements in DNA analysis techniques. We honor Susan's memory as we bring this suspect to justice.”

— Cassie Franklin, Everett Mayor

“I've not met anybody in 19 years who is more dangerous to the community than Mitchell Gaff.”

— Paul Stern, Prosecutor

“Part of my horror is living with what happened to those two little girls while he was on probation for attacking me. I wish I had been able to kill him.”

— Jackie O'Brien

What’s next

The judge in the case will decide on Tuesday whether or not to allow Mitchell Gaff out on bail before his trial begins in September.

The takeaway

This case highlights the ongoing challenges of the criminal justice system in keeping dangerous repeat offenders like Mitchell Gaff off the streets, and the lasting trauma experienced by his victims and their families. It also demonstrates the power of DNA evidence in solving cold cases, even decades later.