BOISE, ID — Idaho authorities say they have identified a man found dead by cyanide poisoning in a Boise church in 1982 and are now examining whether he may have had a connection to the still-unsolved Tylenol murders in Chicago.
The Ada County Sheriff’s Office said the man long referred to as the “unknown wanderer” was Dr. Mathew Francis Betkouski. His body was discovered Dec. 4, 1982, underneath a pew at Sacred Heart Catholic Church. Investigators said Wednesday that Betkouski died after poisoning himself, and that new findings have linked parts of his life to Chicago before the 1982 Tylenol killings.
How a church death in Boise became a wider investigation
Detectives said the case began to sharpen in 2019, when they reopened the cold case and started sorting through items Betkouski left behind. One of the most important breaks came from a key found among 30 items in his possession. The key had an engraving tied to a street in Jacksonville, Florida, which led investigators to a man who went missing in 1982 and was later declared dead in 1989.
A Los Angeles man who spoke with police was identified as that missing man’s brother. According to detectives, the brother’s DNA matched DNA taken from a wallet belonging to the unknown wanderer. Investigators said that helped them identify Betkouski and piece together the broader path his life followed before his death in Boise.
Police say Betkouski had chemistry interests and troubling remarks about cyanide
Authorities described Betkouski as a Ph.D. holder from a prominent Los Angeles family. They said his grandfather had served on the Los Angeles City Council. Police also said he had a documented fascination with chemistry and that his mental health declined after a traumatic brain injury in 1974.
At Wednesday’s briefing, investigators said coworkers heard him talk about cyanide at more than one job. In Florida, they said, he discussed “the perfect crime involving cyanide” before being fired. Police also said that while he was working for Lockheed Martin, he allegedly made a comment about poison in over-the-counter capsules, tried to get pills or capsules “for an experiment,” and took unauthorized material home from the lab.
Evidence from his room tied him to Chicago before the Tylenol deaths
Police said Betkouski had been back at his childhood home in 1979 and again in the early 1980s. In his bedroom, investigators said they found a map of Chicago from the 1970s, writings from 1980 and 1981 that suggested he wanted to visit the area, and a bottle of cyanide.
The bottle police described was sodium cyanide made from peach and apricot pits, which they said was different from the potassium cyanide used in the Tylenol murders. They also found photographs that placed Betkouski in the Chicago area in December 1981, though not in 1982. Investigators said they do not know whether he returned later, during the year the poisonings occurred.
What investigators say happened in the months before his death
Police believe Betkouski traveled to Las Cruces, New Mexico, around Oct. 15, 1982, and sold his car. By the time he was found dead in Boise that December, investigators said, he had dyed hair, a dark tan and new clothes, suggesting he had changed his appearance.
Authorities also said a suicide note and $1,900 were found with his body. The note explained how he wanted the money used for his funeral and cremation, and it was signed with the alias “Wm. L. Toomey.” Betkouski’s father died in 1982, and his brother died in 2021, leaving family members with personal items that detectives were later able to examine.
Chicago police and suburban detectives review the Idaho findings
Idaho authorities said they have sent everything they collected to investigators in the Chicago area. Chicago police said detectives have been in contact with Idaho officials and that anyone with information can submit an anonymous tip online.
Arlington Heights police, whose village is tied to one of the bottles sold in the Tylenol case, said repeated claims over 44 years have not been substantiated. They said the FBI remains the lead agency and that the investigation is still active. Police also said they reviewed information from Ada County and will continue working with law-enforcement partners on any viable leads.
Why the Tylenol murders still draw scrutiny four decades later
The Chicago-area poisonings killed seven people after cyanide-laced capsules were placed in Tylenol bottles bought at drugstores. The victims were Mary McFarland, Mary Kellerman, Paula Prince, Mary “Lynn” Reiner and three members of the Janus family: Stanley, Adam and Terri.
Only one person, James Lewis, was ever charged in the case, and that was for extortion rather than the killings themselves. He was convicted in federal court after writing a letter demanding money and saying he would “stop the killing.” Lewis denied responsibility until his death in 2023, and Chicago-area investigators have continued to treat the murders as unsolved. Idaho detectives say their new identification gives them another line of inquiry, but they have not called Betkouski a suspect.
Local news that matters, from Dulaney Griffin.
