The Unknown Wanderer, a man poisoned inside an Idaho church in 1982, has been identified as Dr. Mathew Francis Betkouski. Investigators have also presented compelling evidence suggesting he may have been connected to the Tylenol murders, in which seven people died after taking cyanide-laced capsules.
The Ada County Sheriff’s Office (ACSO) announced the breakthrough during a press conference on Wednesday morning, ending decades of speculation over the man’s identity.
Betkouski, who was from California, was found dead beneath a pew at Sacred Heart Catholic Church on December 4, 1982, after a confessional service, Ada County Sheriff Matt Clifford said.
He died from cyanide poisoning—the same method used in the Tylenol murders, which claimed seven lives during the final week of September 1982.
Authorities eventually identified Betkouski through one of 30 keys recovered from his body after his death.
ACSO cold case detective Tim Cooper outlined several pieces of evidence linking Betkouski to the killings. However, he stressed that investigators had not been able to conclusively identify him as a suspect.
While working as a chemist at the highly secretive White Sands testing facility in Las Cruces, New Mexico, Betkouski reportedly said that poisoning capsules would be an ideal way to kill someone.
Cooper said Betkouski was fired after a disturbance at a local pharmacy and was known to have a “documented fascination” with chemistry and explosives.
The Ada County Sheriff’s Office revealed on Wednesday that the unidentified man was Dr. Mathew Francis Betkouski
Betkouski was identified through one of 30 keys found on his body after his death (pictured)
Mary Kellerman, 12, Adam Janus, 27, Stanley Janus, 25, Theresa Janus, 19, Mary McFarland, 31, Paula Price, 35, and Mary Reiner, 27, died after taking cyanide-laced Tylenol pills
A woman also died from cyanide poisoning at the facility while Betkouski worked there, although her death remains unsolved.
Years after Betkouski’s death, investigators located his family and visited his childhood home. There, they found a small bottle of cyanide that was “likely homemade,” along with a map of Chicago, Cooper said.
The cyanide found at the home was a different type from the poison used in the Tylenol murders.
Investigators also learned that Betkouski had made several calls to pharmaceutical and chemical supply companies in Pennsylvania just weeks before the Tylenol deaths.
Detective Cooper further pointed to rumors that Betkouski may have confessed inside the Catholic church shortly before his suicide.
Cooper did not disclose the details of those claims, emphasizing that they had never been verified.
According to Sheriff Clifford, Betkouski was carrying a filled keychain, a typed suicide note and $1,900 when he died.
The note said he wanted the money to cover his funeral and cremation costs. It was signed “Wm. L. Toomey.”
Betkouski had never been reported missing. Police used the single key to trace him to Jacksonville, Florida, and then located a living relative who confirmed his identity.
Betkouski, of California, was found dead beneath a pew at Sacred Heart Catholic Church on December 4, 1982, following a confessional service, Ada County Sheriff Matt Clifford said
ACSO Cold Case Detective Tim Cooper then produced multiple pieces of evidence that link Betkouski to the killings, although he said his office was not able to definitively name Betkouski as a suspect
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Cooper said that Betkouski often talked about cyanide, referring to it as ‘a less messy way of taking a person’s life.’
The infamous Tylenol murders claimed the lives of seven people across the Chicago area after they ingested extra-strength Tylenol capsules that were laced with cyanide.
The youngest victim, Mary Kellerman, 12, was the first known person to die.
Just hours later, Adam Janus, 27, died, and while his family was grieving at his home, two more of his relatives, Stanley Janus, 25, and Theresa Janus, 19, passed away after taking pills from the same bottle.
Mary McFarland, 31, Paula Price, 35, and Mary Reiner, 27, also died after taking the tainted pills.
Their deaths triggered a nationwide Tylenol recall and sparked the invention of mandatory tamper-evident safety seals in consumer goods and pharmaceutical industries.
The murders remain unsolved nearly 44 years later.
The deaths triggered a nationwide Tylenol recall and sparked the invention of mandatory tamper-evident safety seals in the consumer goods and pharmaceutical industries
Investigators identified some suspects, but only one man, James Lewis, was convicted after he sent a letter to Johnson & Johnson demanding $10 million to stop the Tylenol deaths
Another man, Roger Arnold, was also investigated by police after he confessed to possessing potassium cyanide – the same substance used in the 1982 murders
Over that time, investigators identified some suspects, but only one man, James Lewis, was convicted.
Lewis wrote a letter around the time of the deadly poisonings to Johnson & Johnson – the former makers of Tylenol – stating that the deaths would stop if the company wired $10 million to a Chicago bank account.
He admitted to writing the letter, but claimed it was only to embarrass a travel company that the bank account was tied to.
In the end, he was convicted of extortion in connection with the letter and sentenced to 10 years in prison.
He was released in October 1995 and died at his home in Cambridge, Massachusetts, in July 2023.
Another man, Roger Arnold, was also investigated by police after he confessed to possessing potassium cyanide – the same substance used in the 1982 murders.
A bar owner, Marty Sinclair, also reported hearing the dock worker discussing killing people with white powder.
He was held several times by police, but never charged.
Arnold did, however, serve time for shooting a man whom he thought was Sinclair, in the summer of 1983.
He was convicted in January 1984 and served 15 years of his 30-year sentence. Arnold died in June 2008.
After his body was exhumed, it was used for DNA testing in the Tylenol case and did not match any of the DNA found on the bottles.