On September 29, 1982, a 12-year-old girl in suburban Chicago took an Extra-Strength Tylenol and died shortly afterward. Six more people in nearby suburbs were dead before law enforcement found the pills were laced with potassium cyanide. The Tylenol bottles came from different factories, suggesting someone had shoplifted the common pain reliever, poisoned the pills elsewhere, then replaced them on supermarket shelves to kill random strangers.

Police pursued leads that dead-ended at spiked cider and squirrels deceased due to natural causes, until Johnson & Johnson received a letter demanding a million dollars to “stop the killings.” Tracking the letter’s author across several states – and through numerous aliases – the cops learned the man they were chasing was James W. Lewis. Lewis had escaped prosecution for murdering and dismembering a 72-year-old Kansas City man in 1978, on the grounds that Lewis wasn’t Mirandized at the time of his arrest. Since then, he’d been working his way through various forms of extortion and fraud.

Though Lewis was the prime suspect, authorities could find no direct evidence tying him to the crime. He was convicted of extortion on October 27, 1983. He served more than 12 years in prison and moved to Boston in 1995. In 2004, Lewis dodged a trial for rape and kidnapping when his alleged victim wouldn’t testify. As recently as 2009, the F.B.I. maintained an interest in Lewis, having searched his residence in February of that year.

The Tylenol murders remain unsolved.