Roger Ressmeyer / Corbis Tylenol capsules are removed from the shelves of a drug store after reports of tampering in February of 1986.

Psychologists called the killer so strange that their normal guidelines "just don't work." And now, more than 26 years after Tylenol capsules laced with potassium cyanide killed seven people in the Chicago area, the Tylenol murders still have enough people scratching their heads that the FBI reopened the case and is taking a fresh look at old suspects.

The murders started in September 1982, when the parents of Mary Kellerman gave the 12-year-old a painkiller when she woke up complaining of a cold. She died hours later. Postal worker Adam Janus died in another Chicago suburb later that morning. Janus' brother and his brother's wife, complaining of headaches while mourning Adam, died too. In a few days the death toll grew  the only link being that each victim had taken Extra-Strength Tylenol. (See the top 10 unsolved crimes.)

On testing, each of the capsules proved to be laced with potassium cyanide at a level toxic enough to provide thousands of fatal doses. Police were baffled  the pills came from different production plants and were sold in different drug stores around the Chicago area. Their conclusion was that someone was most likely tampering with the drug on the store shelves. The deaths set off a nationwide panic, as stores rushed to remove Tylenol from their shelves and worried consumers overwhelmed hospitals and poison control hotlines. Chicago police went through the streets with loudspeakers, warning residents of the dangers of taking Tylenol. Johnson & Johnson, the drug's manufacturer, spent millions of dollars recalling the pills from stores.

The tampering inspired hundreds of copycat incidents across the U.S. The Food and Drug Administration tallied more than 270 different incidents of product tampering in the month following the Tylenol deaths. Pills tainted with everything from rat poison to hydrochloric acid sickened people around the country. Some copycats expanded to food tampering: that Halloween, parents reported finding sharp pins concealed in candy corn and candy bars. Some communities banned trick-or-treating all together.

Police never arrested anyone for the original Tylenol murders, but tax consultant James Lewis wrote a letter to Tylenol's manufacturer in October 1982 demanding $1 million to "stop the killings." Lewis had a strange past. He had been charged with a 1978 Kansas City murder after police found the remains of one of his former clients in bags in his attic; charges were dropped after a judge ruled that the police search of Lewis' home was illegal. But police could never tie him to the Tylenol killings and he denied committing them. Lewis was convicted of extortion for the letter and spent more than 12 years in federal prison. Richard Brzeczek, the Chicago police superintendent at the time, said it was unlikely Lewis would ever be prosecuted for the killings themselves.

But when the FBI reopened their investigation in early February, the focus shifted back to Lewis. His Cambridge, Mass. office was searched as well as a storage unit he had rented nearby. The FBI has been tightlipped about the reason for the search and haven't named Lewis in conjunction with the reopened investigation. Police still have some of the tainted Tylenol capsules from the original killings and are hopeful some DNA can be recovered from the pills for testing.

The killings did have a measurable, positive impact, however: a revolution in product safety standards. In the wake of the Tylenol poisonings, pharmaceutical and food industries dramatically improved their packaging, instituting tamperproof seals and indicators and increasing security controls during the manufacturing process. The result has been a dramatic reduction in the number of copycat incidents  although it may be of little solace to the families of the seven killed in Chicago. But now, as the FBI brings modern technology to bear on a case long gone cold, perhaps they can hope again for something else tangible: at long last, some criminal charges.

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