The Ada County Sheriff’s Office in Boise announced Wednesday that it has identified the man long known as the “Unknown Wanderer,” who died of cyanide poisoning inside Sacred Heart Catholic Church more than four decades ago, as Dr. Mathew Francis Betkouski, an organic chemist with a documented history of talking about cyanide and poison.
Investigators say details uncovered about Betkouski’s background have raised questions about a possible connection to the 1982 Chicago Tylenol murders, in which seven people died after taking cyanide-laced Tylenol capsules during the final week of September that year. That case has never been solved.
Sheriff’s investigators have been careful to note the limits of what they know. They say they cannot place Betkouski in Chicago during the week the poisonings occurred, and they are not naming him as a suspect.
Dr. Park Dietz, a forensic psychiatrist who consulted on the original Tylenol investigation and later reviewed evidence collected on Betkouski, went further than investigators in his assessment.
“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.
Dietz said groups of forensic psychiatrists, psychologists and criminal profilers who reviewed information about Betkouski anonymously overwhelmingly considered him a viable suspect in the poisonings.
How the case was cracked
Betkouski died on Dec. 4, 1982, after walking into Sacred Heart Catholic Church in Boise. He carried no identification, and his fingerprints matched nothing on file, leaving his identity a mystery for decades.
The break came when investigators traced one of nearly 30 keys found on him to Jacksonville, Florida, where Betkouski had once lived. DNA recovered from his wallet was later compared with a sample from his brother, confirming his identity.
That discovery set off a broader look into Betkouski’s past, which turned up details that caught investigators’ attention. A former colleague recalled him discussing the “perfect crime” and cyanide, and another scientist recalled him saying poison could be introduced into over-the-counter capsules, according to investigators.
Searches also turned up a map of Chicago and a bottle of sodium cyanide among belongings kept at his family’s home in Los Angeles. Investigators were careful to point out that this was not the same compound, potassium cyanide, used in the Tylenol poisonings.
Photographs showed Betkouski had visited Chicago at some point, but investigators believe those photos were likely taken in December 1981, nearly a year before the poisonings, and they cannot establish that he returned to the city when the deaths occurred in September 1982.
A vanishing act, then a body in Boise
Betkouski disappeared from his home in New Mexico on Oct. 15, 1982. He turned up dead in Boise seven weeks later, having apparently changed his appearance.
Authorities have now turned their findings over to investigators in the Chicago area and are seeking information about Betkouski’s movements and communications throughout 1982.
“This isn’t over,” Ada County Sheriff Matt Clifford said.
Add comment