We spoke with Joni Johnston, a forensic psychologist, to explore the ancient legacy of poisonings, the psychological profile of a homicidal poisoner and common myths and misconceptions about those who poison.

On Halloween 1974, a Texas man poisoned his young son with cyanide-laced candy in an attempt to collect the insurance money. He became known as 'The Candy Man.'

Dominick Polifrone gained the confidence of the contract killer in an undercover operation that almost cost him his life.

A&E True Crime spoke with Marcus Parks—whose podcast "The Last Podcast on the Left" ran a special on Jonestown—to learn more about the last fateful hours of the men, women and children who died that tragic day.

Experts weigh in on whether the 918 people, including almost 300 children, who died during the Jonestown massacre were victims of suicide or murder.