Dr. Nancy Wu Chen, right, toxicologist for the Cook County medical examiners office, oversees testing of suspected Extra Strength Tylenol capsules by toxicologist Carole Trojan, Oct. 1, 1982. The samples were taken from the residences of victims of the poisoning, which claimed five lives in the Chicago area. An extensive investigation began on Friday involving multiple agencies throughout the metro Chicago area. (AP Photo/Charlie Knoblock)