Idaho detectives identify 1982 Boise suicide victim, explore possible link to Tylenol poisonings
Idaho cold-case investigators have identified the man who died by cyanide poisoning in a Boise church in 1982 as Dr. Mathew Betkouski and are reviewing whether he may have been involved in the 1982 Tylenol murders in Chicago.
Idaho investigators announced Wednesday that they have identified the man who died by suicide inside Sacred Heart Catholic Church in Boise on Dec. 4, 1982. The victim, previously known only as “Unknown Wanderer,” was identified as Dr. Mathew Betkouski, a chemist who had worked in drugstores and a flavors and fragrances company before undergoing psychiatric treatment in the late 1970s.
Detective Tim Cooper of the Ada County Sheriff’s cold-case unit said the identification came after re-examining evidence, including an engraved key that led to a residence in Jacksonville, Florida, and reviewing Betkouski’s personal writings. Those who knew him described a “history of volatility” and a fascination with the “perfect crime” and cyanide as a method of killing.
Betkouski’s brother provided a map of Chicago and a sample of homemade sodium cyanide found among his belongings. Cooper noted that the cyanide used in the Chicago Tylenol poisonings was potassium cyanide, but the difference does not rule out a possible connection. Photographs show Betkouski visited Chicago in 1981, a year before the Tylenol deaths, though it is unclear whether he returned in September 1982.
“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 in the final week of September 1982,” Cooper said at a news conference.
The information has been shared with Chicago and Arlington Heights police, both of which say the Tylenol murders remain an active cold case. The FBI, which leads the investigation, stated that past allegations of links to the killings have remained unsubstantiated and that it will release credible information when evidence permits.
Cooper hopes the disclosure will generate new leads, especially regarding Betkouski’s movements between Oct. 15 and Dec. 4, 1982. He is working with forensic psychiatrist Dr. Park Dietz, who considers Betkouski a “viable suspect.” The case will be featured in an "Unsolved Mysteries" documentary airing Oct. 9 on The Roku Channel.
The Tylenol poisonings have long been attributed to James Lewis, who died in 2023 without being charged. Former U.S. attorney Jeremy Margolis dismissed the Betkouski theory as “utter nonsense.”