DNA CRACKS COLD CASES
Convicted rapist tied to two violent murders in Washington in 1980s
Right: Judy Weaver was 42 when she was killed in 1984. DNA from her crime scene was used to arrest Mitchell Gaff in 2024.
Left: Susan Vesey was killed in 1980, the day after her 21st birthday.
Jackie Brown (now O'Brien) is pictured in her Washington State Patrol uniform in 1981, two years after surviving Mitchell Gaff 's attack in Everett, Wash.
Gaff
SPOTLIGHT| CRIME
When two researchers knocked on Mitchell Gaff 's door and asked if he would try various flavors of their company's gum, the convicted rapist thought he was participating in a harmless taste test. What he didn't know is that the "researchers" were undercover investigators who suspected him of murder and were there to collect DNA evidence.
Now Gaff — a diagnosed "sexual sadist" and admitted rapist — is accused of the gruesome killings of two women after DNA collected from the gum matched separate 1980s crime scenes in Washington state, according to court records.
Gaff , 68, pleaded guilty to two counts of first-degree murder in Snohomish County Superior Court on April 16, according to the Everett Police Department just north of Seattle.
He described the two murders in detail in open court as part of a plea agreement that in all likelihood means he will die behind bars, prosecutor Craig Matheson said.
"This was a good result for the families" of the victims, Matheson said. "They got some answers without any real risk of a jury going rogue or us making a mistake in the court during trial."
Woman fought back
Jackie O'Brien, the first woman to survive an attack by Gaff , recently said she's still furious that Gaff got a slap on the wrist for assaulting her in 1979 and he never should have seen the light of day after he was convicted of violently raping two teenage sisters in their home for more than two hours in 1984.
"Part of my horror is living with what happened to those two little girls while he was on probation for attacking me," O'Brien said. "I wish I had been able to kill him."
As Jackie Brown, 29, put her lawnmower away in her shed in Everett the day before Thanks giving in 1979, Mitchell Gaff , 21, confronted her with what looked like a handgun. He told her to shut up and get on her knees.
Brown, whose married last name is now O'Brien, recently recounted the ordeal. Court records back up her account, and Gaff was convicted of assault with a deadly weapon and burglary in the case.
Once O'Brien was on her knees with her back to Gaff , she said he began beating her head with the gun, punched her and knocked her head on the cement floor and wall.
O'Brien tried to talk him into going to her bedroom, where she kept a gun under her pillow. She was an officer with the Washington State Patrol who interviewed rape victims, and her father taught her how to fight in the event of an attack.
"I thought if I could get him to the bedroom, I'd blow his brains out," she said.
O'Brien said Gaff put down the gun to tie up her wrists.
That's when "I threw my body against him and caught him off guard, and he kind of stumbled against the wall," the now 76-year-old recalled. "I stood up, and I was trapped, and he said, 'You're going to die now, you (expletive).'"
Gaff pulled out a hunting knife and slashed her across a hand that she held up in defense. "Then I shoved him and I went out one way into the garage and alley screaming, thinking he was chasing me."
Gaff fled and changed clothes. Police soon caught him and a K-9 tracked his scent to the spot where he hid a duffel bag full of incriminating evidence. The gear included an air gun, tape, black leather gloves, a stocking cap and a rubber face mask, court records say. In an interview with a psychiatrist in 1994, Gaff said he intended to cut O'Brien's clothing off with his knife and rape her, but denied he intended to kill her, according to court records.
A jury found him guilty and he was sentenced to 30 days of jail with work release — meaning he got to leave daily — and then five years of probation.
Teens attacked
Before his probation was up, Gaff crept into a home in Everett where a mother and her teenage daughters slept late Aug. 28, 1984.
Gaff , who married, saw one of the teenagers that day and followed her home — less than 4 miles from O'Brien's home, according to court records.
Gaff hogtied the 14and 16-year-old girls with an electrical cord, cut off their clothes with a knife, raped them repeatedly, beat and choked them and shocked one of them with an electrical cord, court records say. The younger girl was able to escape to get help; he fled.
Gaff pleaded guilty to two counts of rape and burglary in the case. In subsequent court hearings, he admitted he tried to attack up to 30 women and girls a day in the early 1980s and confessed to raping at least eight of them, according to court records and archived news reports.
He was sentenced to 11½ years in prison.
In 2006, Gaff was released to a halfway house in Seattle. For the next decade, he went back and forth from so-called transition facilities to total confinement due to violations of court-ordered conditions.
In multiple interviews and court hearings, he blamed months of sexual abuse by a female babysitter when he was a boy, combined with alcohol and drug abuse as an adult.
Murder charges
Gaff was 66 and living on his own in Olympia when two undercover female detectives with the Everett Police Department knocked on his door in 2024, introducing themselves as researchers with the gum industry, according to court records.
The gum was sent to a lab to extract DNA and see whether it matched crimes in a national database known as CODIS.
Months earlier, detectives zeroed in on Gaff when DNA collected from a wrist ligature in the 1984 cold case killing of a mother of two named Judy Weaver, 42, got a hit on CODIS.
Firefighters responded to a fire at Weaver's apartment June 1, 1984, and found her dead inside. Her clothes were cut off , she was hogtied with an extension cord and a drawstring, and she had been raped, beaten and strangled, court records say. A butcher knife lay near her body, and the killer started a fire.
DNA from Gaff 's gum came back in 2024 as consistent with evidence collected from Weaver's body, court records say. He was arrested in May 2024.
In January 2025, Everett police cold case Detective Susan Logothetti returned a call from an angry man demanding to know why there was no progress in the investigation of his wife's 1980 death in Everett. As the man described the murder, Logothetti recognized "startling similarities" with Weaver's killing, according to court records.
On July 12, 1980, Susan Vesey's husband came home from work to find his wife brutally killed the day after her 21st birthday. Their 3-monthold baby was in his crib and their 2-year-old daughter was walking around.
Vesey was tied up with an electrical cord, her clothes were mostly removed and she had been sexually assaulted and strangled, court records show.
DNA from pieces of cord used to bind Vesey matched Gaff , court records say. He was charged March 13 with her murder.
"I am so proud of our Everett Police Department for solving this murder case by utilizing advancements in DNA analysis techniques," Everett Mayor Cassie Franklin said in a statement. "We honor Susan's memory as we bring this suspect to justice."
