Early on the morning of Sept. 29, 1982, a tragic, medical mystery began with a sore throat and a runny nose. It was then that Mary Kellerman, a 12-year-old girl from Elk Grove Village, a suburb of Chicago, told her mother and father about her symptoms. They gave her one extra-strength Tylenol capsule that, unbeknownst to them, was laced with the highly poisonous potassium cyanide. Mary was dead by 7 a.m. Within a week, her death would panic the entire nation. And only months later, it changed...
