A 68-year-old Washington State man has pleaded guilty to murdering two women in the 1980s after investigators obtained DNA evidence through an unusual undercover operation. Mitchell A. Gaff acknowledged killing Susan Vesey, found dead in her Everett apartment on July 12, 1980, and Judy Weaver, whose body was discovered on June 2, 1984.

Detectives reopened Weaver's case in 2020 and linked DNA to Gaff in 2023. In January 2024, undercover officers posing as market researchers for a gum company approached Gaff and collected his chewed gum, which provided a DNA sample matching evidence from both crime scenes. The DNA matched vaginal swabs, ligatures from Weaver's neck and wrists, and clothing cut from her body. Gaff had prior convictions for violent rapes committed just months before Weaver's murder.

Jackie O'Brien, who was assaulted by Gaff in 1979, said she wanted him to go through a trial. "His punishment for what he did to me wasn't severe enough," she said. "As soon as he got out of jail, he raped and sodomized those two little girls." Gaff is scheduled for sentencing on May 13.