Boise mystery solved. Could it be a break in the infamous 1982 Tylenol killings?

Sally Krutzig, The Idaho Statesman on Sep 23, 2026

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BOISE, Idaho — A dead man whose identity long remained a mystery in Boise might be responsible for the infamous Chicago Tylenol killings — widely considered one of the greatest unsolved cases in U.S. history.

One of Boise’s most mysterious cold cases surrounded an unidentified man who died by suicide after taking a fatal dose of cyanide on Dec. 4, 1982, in Boise’s Sacred Heart Catholic Church. Parishioners discovered him under a pew.

The “Unknown Wanderer,” as he was dubbed, was found with a number of possessions on his person, including two key rings containing nearly 30 keys, $1,900 and a note asking to be cremated that was signed by Wm. L. Toomey, which turned out to be a false name, according to the Ada County Sheriff’s Office.

The case, which was featured on the television show “Unsolved Mysteries” in 1990, soon went cold and wasn’t looked into further until Ada County Detective Tim Cooper reopened the case in 2019 on the suggestion of a member of Sacred Heart.

Seven years later, the Ada County Sheriff’s Office revealed at a Wednesday morning news conference that it had ascertained the man’s real identity: Mathew Betkouski, a chemist born to a prominent Los Angeles family.

But Cooper found something even stranger as he looked into Betkouski. Cooper said he uncovered evidence indicating a potential connection to the 1982 Tylenol poisonings that claimed seven lives in the Chicago area after over-the-counter pain capsules were laced with cyanide.

Ada County Sheriff Matt Clifford made it clear that his office was not naming Betkouski as an official Tylenol suspect on Wednesday. It would be up to law enforcement in Chicago to do that.

Unveiling the Unknown Wanderer

The key to solving the mystery of Betkouski’s identity turned out to be an actual key. The Ada County Sheriff’s Office consulted local Boise key experts, who helped trace one of the Unknown Wanderer’s keys to a street in Jacksonville, Florida. Law enforcement pulled land deeds from all former residents and learned that a man named Betkouski, who went missing in 1982, had once owned a home there, according to Cooper.

The Ada County Sheriff’s Office said detectives tracked down Betkouski’s surviving brother and compared his DNA to that of the man found in Sacred Heart. It confirmed that the Unknown Wanderer was, in fact, Betkouski.

Possible tie to Tylenol killings

As detectives looked into Betkouski, they found some concerning information.

The Sheriff’s Office explained that from 1979 to 1982, Betkouski worked on a NASA-related project at the White Sands Test Facility in Las Cruces, New Mexico. His time there ended after he created a “disturbance” at a local pharmacy while attempting “to obtain some type of pills or capsules” that he said were “for an experiment,” Cooper said. He was also found to have been taking home unauthorized material from the lab, according to the detective.

“A fellow scientist from the White Sands Test Facility recalled that, before he was terminated, Dr. Betkouski made a comment about how poison could be introduced into over-the-counter capsules if a person wished to do so,” Cooper said.

Cooper said they also discovered that the Las Cruces Police Department had an unsolved cyanide poisoning from May 1982.

The Sheriff’s Office traveled to Los Angeles to examine some of Betkouski’s possessions kept by his remaining family members. Among his things, they found a map of Chicago made in the late 1970s and a bottle of what appeared to be homemade cyanide, according to Cooper.

“This was sodium cyanide,” said Cooper, indicating this was not definitive evidence. “This was not potassium cyanide, as was used in the Chicago-area deaths in 1982.”

In 2024, the Sheriff’s Office found photos showing that Betkouski did visit the Chicago area.

“Subsequent investigation revealed these photos were likely taken in December of 1981,” Cooper said. “So, at this time, it’s unclear if Dr. Betkouski returned to Chicago in 1982, and we cannot place him in Chicago in the final week of September 1982.”

The Ada County Sheriff’s Office said it plans to continue investigating the case.

“Detective Cooper has done amazing work, but there are still a lot of questions we don’t have answers to, and that’s part of why we’re standing here today,” Clifford said. “So I’m not going to beat around the bush with everybody, but this isn’t over, and what you’ve heard today could take months or even years to fully work through.”

The sheriff asked anyone with information on this case to contact the Ada County Sheriff’s Office at ACSOtips@adacounty.id.gov.

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