The man known for decades as the “Unknown Wanderer,” who died after being poisoned inside an Idaho church in 1982, has been identified. Investigators have also presented evidence suggesting he could have been connected to the infamous Tylenol murders, in which seven people died after taking cyanide-laced capsules.
At a news conference Wednesday morning, the Ada County Sheriff’s Office (ACSO) identified the man as Dr. Mathew Francis Betkouski.
Ada County Sheriff Matt Clifford said Betkouski, who was from California, was discovered beneath a pew at Sacred Heart Catholic Church on December 4, 1982, after a confessional service.
His cause of death was cyanide poisoning—the same method used to kill the Tylenol victims during the final week of September 1982.
Authorities eventually identified Betkouski using one of 30 keys found on his body. The mysterious key collection was later featured in a well-known 1990 episode of Unsolved Mysteries. At the time, investigators did not connect him to the Tylenol killings.
ACSO cold case detective Tim Cooper outlined several details that could tie Betkouski to the murders. However, he stressed that investigators have not been able to conclusively identify him as a suspect.
While employed as a chemist at the highly secretive White Sands testing facility in Las Cruces, New Mexico, Betkouski reportedly remarked that poisoning capsules would be an ideal way to kill someone.
Cooper said Betkouski was fired after an incident at a local pharmacy and had a “documented fascination” with chemistry and explosives.
The Ada County Sheriff’s Office identified the previously unknown man as Dr. Mathew Francis Betkouski during a Wednesday morning news conference.
Investigators identified Betkouski through one of the 30 keys found on his body after his death.
Mary Kellerman, 12; Adam Janus, 27; Stanley Janus, 25; Theresa Janus, 19; Mary McFarland, 31; Paula Price, 35; and Mary Reiner, 27, all died after taking cyanide-laced Tylenol capsules.
A woman also died from cyanide poisoning at the facility while Betkouski worked there. Her death has never been solved.
Years after Betkouski’s death, authorities located members of his family and visited his childhood home. There, Cooper said, they found a small bottle containing cyanide that was “likely homemade,” along with a map of Chicago.
Investigators noted, however, that the cyanide was a different type from the poison used in the Tylenol murders.
Records also showed that Betkouski had contacted pharmaceutical and chemical supply companies in Pennsylvania by telephone just weeks before the Tylenol deaths.
Cooper said police recovered photographs showing Betkouski in Chicago. Investigators believe the images were probably taken around December 1981.
The detective also addressed rumors that Betkouski may have confessed inside the Catholic church shortly before taking his own life.
Cooper declined to repeat the details, emphasizing that the alleged confession has never been verified.
According to Clifford, Betkouski was also carrying the filled keychain, a typed suicide note and $1,900 when he died.
The note instructed that the money be used to pay for his funeral and cremation. It was signed “Wm. L. Toomey.”
He was never reported as a missing person, but the sole key help police traced him to Jacksonville, Florida, and eventually to a living relative who confirmed Betkouski’s 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
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 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.
