12: The Tylenol Murders: Over-the-Counter Killers

<div>When 52-year-old Bruce Nickell suddenly dropped dead in Washington state, investigators at first thought he'd died of a heart attack. But then a second person collapsed, and police realized that the two victims had both taken the painkiller Excedrin. Suddenly, they realized they were dealing with a copycat of a case that had haunted federal investigators for nearly 15 years. <br> <br> </div> <div>In that earlier case, seven people died when someone randomly tampered with the over-the-counter painkiller to replace some of the powder inside capsules with enough cyanide to kill an entire family. Those deaths changed how medication is packaged nationwide and made it a federal crime to tamper with such products -- a legal change that years later came back to bite Nickell's killer. </div>