Peggy Carr developed mysterious flu symptoms that no doctor was able to diagnose, until a neurologist noticed her ailments were similar to that of a person poisoned by Thallium. Pye Carr instantly became a prime suspect when the poison eventually killed his wife Peggy. Although there were traces of the poison around Pye's belongings, the FBI did not feel Pye matched the psychological profile of the killer. Instead, they turned their attention to the Carr's next door neighbor George James Trepal, who had an extensive chemistry background and even used Thallium poisoning as a plot device in a MENSA Murder Mystery Weekend that he hosted.