# Identification of potential Tylenol murder suspect

> Live situation record from CLSTR: https://clstr.news/situations/identification-of-potential-tylenol-murder-suspect
> Updated: 2026-09-23T15:33:27.000Z. Sources: 20. Developments: 2.

Investigators have identified Dr. Mathew Francis Betkouski, an organic chemist known as the ‘unknown wanderer,’ as a potential suspect in the 1982 Tylenol murders in Chicago. Betkouski was found dead in a Boise, Idaho, church in December 1982 after consuming cyanide. While police noted that homemade cyanide found among his belongings differed from the poison used in the Chicago killings, investigators discovered maps of Chicago and photos of Betkouski in the city among his possessions.

Following a breakthrough in the cold case, the Ada County Sheriff’s Office confirmed Betkouski’s identity through DNA comparison after tracing property records linked to a key found with his body. Betkouski had died by suicide in 1982, leaving behind a note using the alias ‘Wm. L. Toomey.’ Authorities are now sharing these findings with Chicago-area officials to determine if he was responsible for the cyanide-laced capsules that caused at least seven deaths.

New details indicate Betkouski had a history of mental health treatments and worked in a lab where he allegedly took chemicals. Forensic psychiatrist Dr. Park Dietz stated that both forensic psychiatrists and an FBI group considered Betkouski a viable suspect. While investigators note they lack a ‘smoking gun’ to definitively name him as the killer, they have highlighted links including his professional background in chemistry, his history of volatility, and reported comments he made regarding the introduction of poison into medication capsules. The Chicago Police Department is currently collaborating with Idaho authorities to investigate these connections.

## Claims

- The deceased man has been identified as Dr. Mathew Francis Betkouski, an organic chemist. (corroborated by 10 sources)
- There is a possible connection between Betkouski and the 1982 Tylenol poisonings in Chicago. (corroborated by 7 sources)
- The case was reopened in 2019 by Detective Tim Cooper. (corroborated by 5 sources)
- An engraved key found with the body in the Boise church led investigators to a street in Jacksonville, Florida. (corroborated by 4 sources)
- The identity of the man known as the 'Unknown Wanderer' has been revealed. (corroborated by 3 sources)
- DNA comparison between a surviving brother and material from the man's wallet confirmed his identity. (corroborated by 3 sources)

## Timeline

### 2026-09-23: Mathew Francis Betkouski identified as Idaho’s ‘Unknown Wanderer’

Idaho authorities have identified the ‘Unknown Wanderer’ as Dr. Mathew Francis Betkouski, a chemist who died in 1982. His identity may link him to the unsolved 1982 Chicago Tylenol murders.

12 sources. https://clstr.news/cluster/boise-authorities-identify-unknown-wanderer-as-potential-tylenol-killer

### 2026-09-22: Mathew Francis Betkouski identified as potential Tylenol murder suspect

A cold case investigation into the 1982 Tylenol murders has identified Mathew Francis Betkouski as a potential suspect. Meanwhile, Houston announces a $150 million mall redevelopment.

8 sources. https://clstr.news/cluster/philadelphia-teen-killed-in-corner-store-shooting

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Cite as: Identification of potential Tylenol murder suspect. CLSTR, https://clstr.news/situations/identification-of-potential-tylenol-murder-suspect