It’s almost unimaginable today — a police car slowly moving down your street, its loudspeaker blaring: “Do not take Tylenol until further notice.”
But that was indeed the scene in Chicago’s suburbs in the fall of 1982.
The events that led to those warnings sent chills down the spines of millions of Americans.
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A string of unsolved murders is the subject of a CNN Original Series documentary — How It Really Happened: Tylenol Murders.
The scare began when 12-year-old Mary Kellerman from Elk Grove Village, Illinois, told her parents she was feeling sick on the morning of September 29, 1982.
She wanted to stay home from school. After taking one Tylenol capsule, Mary collapsed on the bathroom floor. She died shortly after.
The same day Kellerman took that Tylenol, less than 10 miles (16km) away in Arlington Heights, Illinois, 27-year-old postal worker Adam Janus took two capsules of Tylenol.
He later died at a nearby hospital.
Adam’s family was in shock. When they gathered that afternoon, Adam’s brother Stanley Janus and Stanley’s wife, Theresa, also took Tylenol capsules from the same bottle.
Both dropped to the floor and were later pronounced dead.
Over the next few days, three more people in the Chicago suburbs would die after taking Tylenol: Mary McFarland, 31, Paula Prince, 35, and Mary “Lynn” Reiner, 27, who had just delivered her fourth child.
In total, seven people — all from the same general suburban area of Chicago — died.
The first indication that Tylenol played a role in the deaths came when Helen Jensen, who was then the Arlington Heights Village Nurse, visited the Janus home and noticed that six capsules were missing from the same Tylenol bottle.
Health officials later found that the capsules had been taken apart and the Tylenol powder was replaced with potassium cyanide.
Within just a few days, a nationwide recall of Tylenol Extra Strength, 500mg, was underway.
Johnson & Johnson recalled at least 31 million bottles.
It was the first mass recall in American history — and it started a murder investigation that would take more improbable twists and turns than a Sherlock Holmes mystery.
The most compelling suspect was James William Lewis, who investigators determined had sent a threatening letter to Johnson & Johnson, demanding $1 million to stop the Tylenol murders.
However, as the investigation expanded, the extent of Lewis’s involvement became more murky. He was convicted of attempted extortion and sentenced to 10 years in prison.
During his sentence, he volunteered to help officials solve the Tylenol killings.
Lewis offered numerous theories as to how the crime could have been committed.
He defended his assistance in a 1992 CNN interview, saying: “If I were going down the street and your house was on fire, not my problem, but I would stop and try to help.”
He served his full sentence and became a free man.
Other suspects were considered, including a dockworker named Roger Arnold.
DNA samples were even requested from Ted Kaczynski, the “Unabomber”.
However, officials could never definitively link Arnold or Kaczynski to the poisonings.
To this day, the mystery of the Tylenol killer endures.
Recent developments, including a collaboration between law enforcement and a prominent biotech firm in Texas, bring hope that access to new DNA technology can solve the case.
As horrific as those deaths remain, the Tylenol murders did lead to safety measures which have very likely saved many lives.
The US adopted tamper-resistant packaging on all over-the-counter medicines as a result, while Australian packaging is made to be tamper-evident rather than resistant.