Idaho police believe 1982 suicide victim is likely Tylenol Murderer

Investigators have identified a man found dead in an Idaho church in 1982 as Dr. Mathew Francis Betkouski, a California doctor whom authorities now believe is likely responsible for the infamous Tylenol Murders that killed seven people.

Betkouski, nicknamed the "Unknown Wanderer" after his death, died by suicide via cyanide poisoning on December 4, 1982, beneath a pew at Sacred Heart Catholic Church in Boise. This was the same method used in the Tylenol murders, which occurred in the final week of September 1982.

The breakthrough in identifying Betkouski came from one of 30 keys found on his body. This key led investigators to an address in Jacksonville, Florida, where property records showed Betkouski had lived until 1989. Although he was not reported missing and was declared dead in absentia in 1989, his continued presence on property records explained the discrepancy.

Forensic scientists confirmed Betkouski's identity after a DNA sample from a relative closely matched genetic material taken from him. Cold Case Detective Tim Cooper of the Ada County Sheriff's Office presented evidence linking Betkouski to the killings, though he acknowledged the lack of a definitive "smoking gun."

Evidence suggests Betkouski had a fascination with chemistry and explosives. While working as a chemist at the White Sands testing facility in New Mexico, he reportedly discussed how poisoning capsules would be an effective murder method. He was fired from the facility after a disturbance at a local pharmacy. During his time there, a woman died from cyanide poisoning in an incident that remains unsolved.

Investigators later uncovered a small bottle of likely homemade cyanide and a map of Chicago at Betkouski's childhood home. He also made phone calls to pharmaceutical and chemical supply companies in Pennsylvania weeks before the Tylenol homicides. Photographs were recovered showing Betkouski visiting Chicago around December 1981.

While unverified, Cooper mentioned rumors that Betkouski may have made a confession in the Catholic Church shortly before his suicide. At the time of his death, Betkouski had a keychain, a typed suicide note signed "Wm. L. Toomey," and $1,900, which he requested be used for his funeral and cremation.

Cooper noted that Betkouski often spoke about cyanide, referring to it as "a less messy way of taking a person's life."

The Tylenol murders claimed the lives of Mary Kellerman, 12, Adam Janus, 27, Stanley Janus, 25, Theresa Janus, 19, Mary McFarland, 31, Paula Price, 35, and Mary Reiner, 27, after they ingested cyanide-laced Tylenol capsules. The incidents prompted a nationwide recall and led to the implementation of mandatory tamper-evident safety seals for consumer goods and pharmaceuticals.

Over the years, several individuals were investigated, including James Lewis, who was convicted of extortion for demanding $10 million from Johnson & Johnson. Roger Arnold was also investigated after confessing to possessing potassium cyanide, but DNA testing from his exhumed body did not match samples found on the Tylenol bottles. Another man, Marty Sinclair, was also looked into but never charged.