Ada County authorities have identified the man long known as the “Unknown Wanderer” — found dead of cyanide poisoning inside a Boise church more than four decades ago — as Dr. Mathew Francis Betkouski, an organic chemist whose past has prompted new questions about a possible connection to the unsolved 1982 Chicago Tylenol murders. The Ada County Sheriff’s Office announced the identification on Wednesday.
Not a named suspect; key Chicago week unproven
Investigators said they cannot place Betkouski in Chicago during the final week of September 1982, when seven people died after taking Tylenol capsules laced with cyanide, and they are not naming him as a suspect.
Expert opinion raises the stakes
Forensic psychiatrist Dr. Park Dietz, who was consulted during the original Tylenol investigation and reviewed evidence gathered on Betkouski, offered a sharper view. “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 at the Ada County Sheriff’s Office. He added that groups of forensic psychiatrists, psychologists and criminal profilers who were anonymously presented with information about Betkouski overwhelmingly considered him a viable suspect.
How the ‘Unknown Wanderer’ got a name
Betkouski died on Dec. 4, 1982, after walking into Sacred Heart Catholic Church in Boise. Authorities determined cyanide poisoning, but he carried no identification, and his fingerprints produced no match. The case endured until investigators traced one of nearly 30 keys found on him to Jacksonville, Florida, where Betkouski had lived. DNA recovered from his wallet and compared with a sample from his brother helped establish his identity.
Clues and limits: cyanide, a Chicago map, and old photos
According to investigators, a former colleague recalled Betkouski discussing the “perfect crime” and cyanide, while another scientist recalled him saying poison could be introduced into over-the-counter capsules. Authorities said they also found a map of Chicago and a bottle of sodium cyanide among belongings kept at his family’s Los Angeles home. Investigators stressed that the poison found was not the potassium cyanide used in the Tylenol murders.
Photos showed Betkouski had visited Chicago, but investigators said the images were likely taken in December 1981 and that they cannot establish he returned when the poisonings occurred.
Timeline and ongoing appeal for tips
Investigators said Betkouski disappeared from his New Mexico home on Oct. 15, 1982, and turned up dead in Boise seven weeks later after apparently changing his appearance. The Ada County Sheriff’s Office said it has turned its findings over to investigators in the Chicago area and is seeking information about Betkouski’s movements and communications in 1982. “This isn’t over,” Ada County Sheriff Matt Clifford said.
