A seemingly trivial piece of discarded chewing gum provided the breakthrough evidence that helped convict Mitchell Gaff of two cold case murders spanning decades. The forensic breakthrough highlights the critical role of modern DNA technology in solving long-unsolved crimes.
The Breakthrough: Gum and DNA Evidence
In January 2024, Mitchell Gaff encountered three undercover detectives posing as chewing gum promoters in Everett, Washington. During this interaction, Gaff unknowingly left behind a sample of saliva on a piece of gum. This single piece of evidence proved crucial for investigators.
- The Encounter: Detectives, including Susan Logothetti, engaged Gaff in a taste test of various gum flavors.
- The Evidence: The saliva collected from the gum provided the necessary DNA sample to link Gaff to historical crimes.
The Murders and Investigations
The investigation focused on two separate, decades-old murders: Judy Weaver (1984) and Susan Vesey (1980). Initially, these cases were treated as unrelated, leading to no prosecutions despite initial leads.
Details of the Crimes:
- Susan Vesey: Murdered in her apartment in July 1980. Gaff admitted to tying up, beating, raping, and strangling her.
- Judy Weaver: Attacked by Gaff four years later. He reportedly set the scene on fire in an attempt to destroy evidence.
Forensic Science Connects the Cases
Forensic advancements were key to connecting the dots across the decades. The initial investigation into Weaver’s murder in 1984 was hampered by the limitations of forensic science at the time.
- Modern Techniques: Investigators utilized advanced software like STRmix to analyze the DNA profile from the gum. This software allowed them to subtract known DNA (from Weaver and her boyfriend) to isolate the profile of an unknown third person.
- Database Match: The resulting profile was entered into the Combined DNA Index System (CODIS), a national database. In November 2023, the profile matched Mitchell Gaff, who was already in the database for prior violent rapes.
- Confirmation: DNA extracted from Gaff’s gum was found to be consistent with samples taken from Weaver’s body, including vaginal swabs and clothing.
Gaff's Confession and Sentencing
Facing the evidence, Gaff, 68, admitted to the killings of both Weaver and Vesey. He is scheduled for sentencing, where he faces up to life in prison.
- Plea: Gaff pleaded guilty to the murders of Judy Weaver and Susan Vesey.
- Impact: The successful identification of the killer has provided closure for the victims' families and brought relief to survivors.
Background on Mitchell Gaff
Court documents reveal a history of violence involving Gaff:
- 1979: He attacked Jacalyn O’Brien, a Washington State Patrol officer, in her garage. During this assault, he slashed her palm. O'Brien later fought back and escaped.
- Diagnosis: Gaff was diagnosed by mental health experts at the time as a "sexual sadist."
- Convictions: He was convicted for the 1979 attack and later for the 1984 attacks, receiving multiple sentences over the years.
