A man who poisoned himself with cyanide in an Idaho church more than 40 years ago has been identified, and investigators say he may be connected to the 1980s Tylenol murders that remain unsolved.
Authorities in Idaho announced the new developments at a press conference Wednesday.
Who is Mathew Francis Betkouski?
What we know:
According to the Ada County Sheriff’s Office in Boise, on Dec. 4, 1982, a man walked into a Catholic church in Boise and fatally poisoned himself with cyanide.
He had a note with a fake name and did not have identification on him. The man was not identified at the time and was buried anonymously. He was known as the "Unknown Wanderer."
In 2019, detectives reopened the cold case investigation and eventually identified the man as Dr. Mathew Francis Betkouski, an organic chemist and "brilliant man who struggled to connect with people in life."
What they're saying:
"This is a case that involves mental illness, and there were a lot of people who tried to get [him] help," Detective Tim Cooper said.
An engraved key found with his body led investigators to a street in Jacksonville, Florida, where a property owner disappeared in 1982. They used photos and DNA testing to confirm his identity.
Ada County Sheriff Matt Clifford speaks at a press conference Wednesday, Sept. 23, 2024 (Ada County Sheriff's Office/Facebook)
Once detectives identified Betkouski and began to learn about him, they came to believe he was a possible suspect in the killings of seven people in the Chicago area with cyanide-laced Tylenol.
Investigators say Betkouski worked in drugstores. Former colleagues and acquaintances said he had a history of volatility, was fascinated by the idea of a "perfect crime" and once said cyanide was a means to kill without detection, authorities said.
Detectives also found cyanide in Betkouski’s desk. It appeared to be homemade and was a different compound than what was used in the 1982 killings.
Betkouski lived in five states throughout his life but never in Illinois or close to Chicago, according to investigators. Photos showed that Betkouski visited the Chicago area a year before the killings, but it was not clear if he returned the following year.
What we don't know:
The Chicago Police Department says it has been in contact with investigators in Idaho, but they didn’t say whether they consider Betkouski a suspect.
Dr. Park Dietz, a forensic psychiatrist who was consulted during the original Tylenol investigation and reviewed the evidence gathered on Betkouski, said Wednesday that he believes Betkouski is a viable suspect.
"It's an extraordinary thing to have been around at the beginning in 1982, and now today in 2026, to see very likely closure," Dietz said.
What's next:
The Ada County Sheriff’s Office asks that anyone with information on Betkouski and his whereabouts in the ‘70s and ‘80s contact authorities.
"There’s still a lot of questions we don’t have answers to," Ada County Sheriff Matt Clifford said. "This isn’t over."
What were the Tylenol murders?
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LiveNOW & Then full episode: Archived coverage of the 1982 Tylenol murders
The children who experienced the scarier-than-usual Halloween of 1982 are grown up now, with children of their own. But some will never forget the Tylenol cyanide murders that year. Here's how it was covered on TV news at the time.
The backstory:
The seven murders in the Chicago area, collectively known as the "Tylenol murders," started on Sept. 29, 1982.
Early that morning, 12-year-old Mary Kellerman came down with a sore throat and a runny nose, so her parents gave her one extra-strength Tylenol. Hours later, she was dead.
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Over the next several days, six more people in the Chicago area died suddenly after taking what was, at the time, the best-selling over-the-counter pain reliever.
Investigators soon realized that each victim had swallowed a tablet laced with a lethal dose of cyanide. The pill manufacturer, Johnson & Johnson, determined that the bottles had been tampered with after leaving the factory.
Someone had taken the bottles off the shelves at several drug stores, added poison to the capsules and then put them back, with unwitting customers purchasing the deadly concoctions.
Stores immediately pulled the drug from their shelves, but consumers across the country were still uneasy as they hunted through their medicine cabinets for bottles with the questionable manufacturing code.
Days after the poisonings, Johnson & Johnson received a letter taking credit for the murders and threatening more – unless $1-million was wired to a Chicago bank account.
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Investigators quickly identified the author as a man named James Lewis. After a two-month manhunt, he was arrested in New York. The next year, Lewis was convicted of attempted extortion and sentenced to prison – but he continued to insist he wasn’t the actual killer, and he was never charged with those crimes.
Roger Arnold, a Chicago dockworker, also got investigators’ attention when a bartender told police that Arnold had been talking about cyanide. Arnold later shot and killed another man, mistaking him for the bartender. He was sentenced to prison for the murder.
Meanwhile, Lewis was released from prison in 1995. Investigators kept an eye on him and even searched his home in 2009, but never ended up filing charges. He died of natural causes in 2023 at the age of 76.
The protective, child-proof seal you see on over-the-counter pain medication today is because of what happened in Chicago. The killings remain unsolved.
The Source: This article includes information from the Ada County Sheriff’s Office in Idaho, The Associated Press and previous FOX Local reporting.