Investigators with the Ada County Sheriff’s Office in Boise, Idaho, say they believe a man who died by suicide inside a Catholic church in December 1982 may have been responsible for the unsolved Tylenol murders that killed seven people in the Chicago area that same year.
According to a news release from the sheriff’s office, the man found dead in the church carried no identification—only a large sum of cash and a typed letter bearing a false name. Cold case Detective Tim Cooper reopened the file in 2019 and, using photographs and DNA evidence, concluded the deceased was Dr. Mathew Betkouski, a man previously reported missing in Florida in 1982.
The sheriff’s office says Betkouski had worked in two drugstores during college and had spoken with others about how cyanide could kill without detection. Cooper said Betkouski’s life took him through several states: “Mathew Betkouski lived in five states over the course of his life — California, Texas, New Mexico, Ohio and Florida.” He added, “We’re hoping that getting his story out generates new leads, not just for this case, but for others we may not even know about yet. I’m especially interested in learning more about his movements between Oct. 15 and Dec. 4, 1982.”
Cooper, quoted by the Hollywood Reporter, described Betkouski as “a brilliant man, but he struggled to connect with people in life.” He said Betkouski had “a documented fascination with chemistry and the use of explosives from a young age, and did put others at risk on more than one occasion.” Cooper also said that “in 1974, Dr. Betkouski sustained a traumatic brain injury, which caused some of his problems to manifest in more concerning ways than they had before.”
According to Cooper, Betkouski worked for a flavors and fragrances company near Jacksonville, Florida, beginning in 1975. “After about three years, concerns mounted after co-workers reported Dr. Betkouski discussing the perfect crime and how cyanide could be used as a less messy means of taking one’s life,” Cooper said. He added that Lockheed fired Betkouski in 1982 “following an incident at a local pharmacy,” where Betkouski “attempted to obtain some type of pills or capsules … for an experiment.”
The Original Chicago Case
Seven people in the Chicago, Illinois, area died in a matter of days in the fall of 1982 after someone laced Tylenol capsules with potassium cyanide, according to Chicago History. No suspect was ever identified, and one man who came forward was later exposed as a fraud and imprisoned for attempting to extort the drugmaker’s parent company. The killings led to nationwide product recalls and prompted new federal tamper-evident packaging requirements for over-the-counter medications.
Forensic psychiatrist Dr. Park Dietz has said that by 2021 he came to believe Cooper “was making connections that linked Betkouski to the Tylenol case.” The Ada County Sheriff’s Office says it has shared its findings with the Chicago Police Department.
Additional details are expected in an upcoming episode of Unsolved Mysteries titled “Unmasking the Tylenol Killer,” set to premiere Oct. 9 on The Roku Channel. Series director Terry Dunn-Meurer said the episode contains “never-before-seen evidence about this new possible suspect in the Tylenol murder case.” The show’s official account promoted the premiere date in a Sept. 23, 2026 post on X.
Cooper is asking the public for any information about Betkouski’s whereabouts and activities, particularly between Oct. 15 and Dec. 4, 1982, saying the sheriff’s office hopes publicizing the case will surface new leads—not only for this investigation but for others that remain unknown.
