Ada County identifies 1982 'Unknown Wanderer,' cites possible Tylenol murders link

Key etchings and Jacksonville property records broke the four-decade cold case

The Ada County Sheriff’s Office on Wednesday named Dr. Mathew Francis Betkouski as the man known for more than four decades as the Unknown Wanderer — the unidentified man found dead from cyanide poisoning inside Sacred Heart Catholic Church in Boise on Dec. 4, 1982. The body had no identification; the man carried an envelope containing 19 $100 bills, a typed note signed “Wm. L. Toomey,” and two key rings holding nearly 30 keys. His hair had been dyed, his nails were finely filed, his skin was unseasonably tanned and his pants were either brand new or recently pressed.

The case went cold for nearly four decades before Detective Tim Cooper reopened it in 2019, after a member of Sacred Heart Church asked him about it in a parking lot. On Wednesday, Cooper told reporters at a press conference that the breakthrough came from etchings on one of the keys found on the body, which indicated it had come from a Jacksonville, Florida, hardware store. Etchings on a second key led detectives to Jacksonville’s Mills Court road.

After acquiring property deeds for the street dating to the 1970s and 1980s, Cooper said, one person stood out — a man who had been pronounced dead in absentia in 1989. The sheriff’s office contacted that man’s only living relative, who said his brother had gone missing in 1982. A DNA sample collected from the body showed “very high probability” that the two shared the same father, Cooper said.

The investigation also produced a record of statements and writings about Betkouski’s interests and mental state. Cooper said Betkouski had worked at two drugstores during his undergraduate studies and had a history of volatility, including a documented fascination with cyanide and explosives. In the late 1970s, while Betkouski was working for a flavors and fragrances company in the Jacksonville area, colleagues became concerned after he discussed “the perfect crime” and how “cyanide could be used as a less messy means of taking one’s life,” Cooper said. “Dr. Betkouski was observed talking to himself on occasions and had fears that he was being tracked,” Cooper said. Writings by Betkouski found by detectives show that he tried to manage schizophrenia and depression and feelings of euphoria brought on by imaginary thoughts of violence.

In late 1979, Betkouski was hired by Lockheed, where a fellow employee recalled him saying that poison could be introduced into over-the-counter capsules, according to Cooper. He was fired in March 1982 after creating an unspecified disturbance at a Las Cruces, New Mexico, area pharmacy while attempting to acquire pills or capsules he said were for an experiment, Cooper said.

Betkouski’s whereabouts after March 1982 are not fully documented. He was last known to be in Las Cruces on Oct. 15, 1982, and was next found dead at the Boise church in December. Detectives found photographs of Betkouski in Chicago, but Cooper said they believed the images were likely taken in December 1981, and that investigators had not been able to place him in Chicago during the final week of September 1982, when at least seven people — including a 12-year-old girl — died in and around the city after consuming potassium cyanide-laced Tylenol capsules.

“So, where this leaves us is while our office may have identified some possible connection between Dr. Betkouski and the 1982 events, we’re not naming him as a suspect and we cannot say he was in Chicago during the final week of September 1982,” Cooper said. “More information does exist in this case that we won’t be releasing today.”

While Cooper was restrained, Dr. Park Dietz, a forensic psychiatrist who was consulted during the initial Tylenol murders investigation and who was brought into the reopened case in 2021, was confident that Betkouski was likely responsible. “It’s an extraordinary thing to have been around at the beginning in 1982 and now, today in 2026, see very likely closure, that the identity of the Tylenol killer from 1982 can be shared,” Dietz told reporters. He said investigators had presented information about Betkouski to groups of forensic psychiatrists, forensic psychologists and criminal profilers, who overwhelmingly considered him a viable suspect, while some “were as convinced as I that Detective Cooper had solved the most important unsolved murder of my lifetime, the Chicago Tylenol murders.”

The Ada County Sheriff’s Office said it has shared its findings with the Chicago Police Department and is asking anyone with information about Betkouski’s whereabouts between Oct. 15 and Dec. 4, 1982, to contact the office. Sheriff Matt Clifford said during the press conference that an Unsolved Mysteries documentary titled “Unmasking the Tylenol Killer” is scheduled to air on Roku on Oct. 9, and that authorities hoped the public exposure would generate additional leads.

“Detective Cooper has done amazing work, but there’s still a lot of questions we don’t have answers to,” Clifford said. “And that’s part of why we’re standing here today. I’m not going to beat around the bush with everybody, but this isn’t over.”