Chewing gum leads to sexual sadist's arrest in 2 cold case murders

This story contains details of violent sexual crimes that readers may find disturbing. They were included to demonstrate the similarities between cases and the terror that victims were forced to endure.

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 Gaff didn't know is that the "researchers" were really undercover investigators who suspected him of murder, and that they were really there to collect DNA evidence.

Now Gaff − a diagnosed "sexual sadist" and admitted rapist − stands accused of the gruesome killings of two women after DNA collected from the gum matched separate crime scenes in the 1980s in Washington state, according to court records.

Gaff, 68, will go to trial on both murder charges five months from now, in September, in Everett, the city just north of Seattle, where prosecutors say he preyed on women. He has pleaded not guilty.

If Gaff is convicted, the new charges would be just the tip of an iceberg of violent sexual crimes in his past, many of which he has admitted in court to committing or in interviews. "I'm a serious piece of crap," he told the Associated Press in 2000.

Jackie O'Brien, the first woman to survive an attack by Gaff, recently told USA TODAY that she's still furious that Gaff got a slap on the wrist for assaulting her in 1979 and that 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."

Neither Gaff nor his attorney has responded to messages seeking comment from USA TODAY.

As prosecutors pursue the murder case against Gaff, USA TODAY is looking back at the crimes he was convicted of, the killings he's now charged with, and the "gum ruse" that landed him back behind bars.

'You're going to die now': Woman who fought back survives

It was the day before Thanksgiving in 1979, and 29-year-old Jackie Brown was mowing the lawn of the home where she lived alone in a charming neighborhood of Everett, about 30 miles north of Seattle.

As she was putting her lawnmower away in a tool shed, 21-year-old Mitchell Gaff confronted her with what looked like a handgun (it was an air gun). He told her to shut up and get on her knees.

Brown, whose married last name is now O'Brien, recently recounted the ensuing ordeal in an exclusive interview with USA TODAY. 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 in the head with the gun, punched her in the head, and knocked her head on the cement floor and wall. All the while, O'Brien was trying to talk him into going to her bedroom in an effort to trick him (she kept a gun under her pillow).

O'Brien knew she had to figure out how to turn the tables. After all, she was an officer with the Washington State Patrol who had interviewed rape victims, and her dad 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.

At some point, O'Brien said that Gaff put the gun down to tie up her wrists. That's when she made her move.

"I threw my body against him and caught him off guard, and he kind of stumbled against the wall," recalled the now-76-year-old. "I stood up, and I was trapped, and he said, 'You're going to die now, you [expletive].' And I knew I was dead."

Gaff then pulled out a hunting knife and slashed O'Brien across a hand that she had 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, changed clothes and stashed his duffel bag filled with incriminating evidence. Police soon caught him coming down a nearby bluff over Puget Sound, and a police K-9 tracked his scent from O'Brien's home to the spot where he had hidden the duffel bag and other gear.

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 had intended to cut O'Brien's clothing off with his knife and rape her, but denied that he intended to kill her, according to court records.

A jury found him guilty and the judge in the case sentenced him to 30 days of jail with work release − meaning he got to leave daily − and then five years of probation.

Before his probation was up, Gaff attacked again.

Mitchell Gaff attacks teenage sisters in their sleep

In the dark of night, Gaff crept up to a home in Everett where a mother and her teenage daughters were sleeping. It was Aug. 28, 1984.

Gaff, who had married, was still on probation for his attack on O'Brien. He had seen one of the teenagers earlier that day and followed her home, located less than 4 miles from O'Brien's home, according to court records.

Once inside, Gaff attacked the 14- and 16-year-old girls, and for the next two and a half hours, put them through living hell as their mother slept in the basement. He hogtied them with an electrical cord, cut off their clothes with a knife, raped them repeatedly, beat them, choked them, and shocked one of them with an electrical cord, court records say. The younger girl was able to escape and get help as Gaff began choking her sister with the electrical cord.

Gaff fled and the girls survived.

Gaff pleaded guilty to two counts of rape and burglary in the case. In subsequent court hearings, Gaff admitted that 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.

"I've not met anybody in 19 years who is more dangerous to the community than Mitchell Gaff," Paul Stern, who prosecuted Gaff, said in 2000.

Gaff described the attack on the teenage sisters in detail in a lengthy interview with GQ magazine in 1995, more than 10 years after the crime. The story by noted journalist Tom Junod, called "The Rapist Says He's Sorry," explores the idea that for people like Gaff − no matter how many years of intensive therapy and treatment − the monster within may never go away.

"Mitch Gaff is or has been a human being who hurts other human beings for sexual pleasure," Junod wrote. "Not out of need, not to gain the dire exigencies of food, shelter, money, transportation and status, but out of want − because he likes it."

A judge sentenced Gaff to 11.5 years in prison for raping the sisters.

A taste of freedom wrecked by a taste of gum

In 2024, Mitchell Gaff was 66 years old, living on his own in Olympia and by all appearances, doing so quietly and legally.

One day, two undercover detectives with the Everett Police Department knocked on his door, introducing themselves as researchers with the gum industry, according to court records.

The female detectives were wearing short shorts and tight T-shirts in hopes that it would get Gaff to participate, according to Gaff survivor Jackie O'Brien, who said one of the detectives later told her the whole story.

The Everett Police Department declined to allow USA TODAY to interview anyone involved in the case, citing concerns about compromising the upcoming trial.

When the detectives asked Gaff to participate in a gum-tasting survey, he agreed, sampling several flavors before discarding them in small cups with lids. Soon, the gum would be sent to a lab to extract Gaff's DNA and see whether he matched any crimes in a national database known as CODIS.

They found exactly what they had hoped for.

Police: DNA connects Mitchell Gaff to 2 cold case murders

Three months before they showed up at his home, detectives zeroed in on Gaff when DNA collected from a wrist ligature in the 1984 cold case killing of a 42-year-old mother of two named Judy Weaver got a hit on CODIS. But detectives wanted to deepen the connection with more testing.

Weaver was killed on June 1, 1984, at her apartment located halfway between the attacks on O'Brien and the teenage sisters. It also came less than three months before the sisters' rapes.

Firefighters responded to a fire at Weaver's apartment and found her dead inside. Her clothes had been 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 was lying near her body, and the killer had started a fire.

DNA from Gaff's gum came back in 2024 as consistent with vaginal swabs and a neck ligature taken from Weaver's body, court records say. He was arrested in May 2024 and has been jailed awaiting trial ever since.

In January 2025, Everett police cold case Detective Susan Logothetti returned a call from an angry man demanding to know why investigators had made no progress in their investigation of his wife's death in Everett in 1980. As the man described the murder, Logothetti immediately recognized "startling similarities" between the case and that of 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-month-old baby was in his crib and their 2-year-old daughter was walking around.

Vesey had been tied up with an electrical cord, her clothes had been mostly removed, and she had been sexually assaulted and strangled, court records show.

Logothetti submitted multiple items from Vesey's crime scene to the Washington State Patrol's forensic lab for updated analysis. In April 2025, DNA from a white cord used to bind Vesey matched Gaff, court records say. In March of this year, another piece of white cord from the crime scene matched Gaff, court records say.

Gaff was charged on March 13 with murder in Vesey's death. He has pleaded not guilty to both Vesey's and Weaver's killings.

“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 shortly after the most recent charges against Gaff. “We honor Susan’s memory as we bring this suspect to justice.”

More about Mitchell Gaff

After Gaff was convicted of raping the teenage sisters in 1984, he served about a decade behind bars in prison and in an intensive sex offender treatment program. But on the day he was supposed to be released in 1994, prison officials told him that he wasn't free to go.

Prosecutors wanted Gaff confined indefinitely under a new state law targeting violent rapists and child molesters who had finished their prison terms but were deemed likely to reoffend. After an ensuing court hearing, a jury found that Gaff was a violent sexual predator, allowing him to be kept under lock and key at the state's Special Commitment Center on McNeil Island in Puget Sound. The arrangement cost the state $550,000 a year, according to archived news reports.

In 2000, at the age of 42, Gaff again sought release. His therapists at the state's commitment center said they thought he was ready after years of intensive therapy, and he said he was a changed man.

"I have an incredible amount of remorse and pain for the innocent people I've harmed," he told the Associated Press at the time, saying that he had learned how to handle his emotions and empathize with his victims. "There was no excuse, no rationalization for what I did to people."

Prosecutors again fought to keep Gaff locked up. Another jury ruled in 2000 that Gaff was a violent sexual predator, and he remained on McNeil Island for another six years.

In 2006, more than 20 years after starting his official prison term, Gaff finally won some measure of freedom. He was released to a halfway house in Seattle, where he lived under constant supervision and could not leave without an electronic tracker.

For the next decade, Gaff went back and forth from so-called transition facilities to total confinement based on various violations of his court-ordered conditions, including viewing sexual content and touching other men in the facilities. In recent years, Gaff appears to have been leading a quiet life in Olympia under a new name and registered as the highest level of sex offender, police say.

Gaff has talked about why he attacked women in multiple interviews and court hearings, blaming months of sexual abuse by a female babysitter when he was a boy, combined with alcohol and drug abuse as an adult.

"I am not what I've done," he told GQ in 1995, saying a switch flipped at the end of more than two years of sex offender treatment. "A giant cog turned inside me, and I was like, 'Yeah! I got it!' It wasn't, 'Oh, I hope I never rape again.' It was, 'I know what to do now so that I don't rape anyone.'"

What happens now?

For now, Gaff is behind bars and being held without bail until his trial in September. His only child, a daughter, has been supportive of him in recent years and has attended many of his court hearings.

Jackie O'Brien told USA TODAY that she's talking with the two sisters raped by Gaff about going to his upcoming trial alongside Judy Weaver's daughters and Susan Vesey's daughter and son. The children of the slain women are now in their 40s and 50s.

Since testifying against Gaff after her attack in 1979, O'Brien has been unable to go to his other court hearings because she didn't want him to see her cry.

This time, it's different. She said she wants to go to the trial to show the judge and jury how Gaff has impacted many lives over the years, to support Weaver's and Vesey's children and the prosecutors, and to show gratitude to the investigators.

"And to show Gaff that I am grateful to have had a small part in putting him behind bars for the rest of his miserable, sniveling life," O'Brien said. "I plan to be there every minute."

Amanda Lee Myers is a senior crime reporter who covers cold case investigations and the death penalty for USA TODAY. Follow her on X at @amandaleeusat.