On September 29, 1982, seven Chicago-area residents were suddenly stricken with a deadly illness. At first doctors were at a loss, but they soon discovered a sinister connection: all the victims had recently taken cyanide-laced Tylenol capsules. This launched an investigation that has lasted over four decades and forever changed the way medications and other goods are packaged in stores. This episode features interviews with family members of the victims, law enforcement who were first responders on that day, medical examiners and investigators on the case.