A week after the killings, investigators had yet to identify any lead suspects. Until the owner of a bar in Chicago made a phone call. And a mysterious letter arrived at the headquarters of Johnson & Johnson. Law enforcement split in their chase for the Tylenol killer, following two different leads. Plus, a turn in the case when the Tribune reporters get unexpected news about a trusted source.

For exclusive details about the Tylenol Murders and a transcript of this episode, visit www.chicagotribune.com/tylenolmurders/