On January 13, 1992, the serial killer changed his plea from not guilty to guilty but insane, which removed the need for a criminal trial and forced the verdict to be based on the jury's decision of his mental state.

Some of the most infamous criminals in history experienced murders first-hand before they starting doing the killing themselves.

Jeffrey Dahmer was just 18 when he committed his first murder, much younger than the average age of serial killers, which researchers have determined is around 29 years old. Why did he wait nearly a decade before killing his next victim?

A&E True Crime speaks with Anne E. Schwartz, a former crime reporter for The Milwaukee Journal, who broke the story about Jeffrey Dahmer's arrest on July 22, 1991, about what it was like uncovering the life and murders of one of America's most notorious serial killers.

What is evil—and how do we measure it? Is it more evil to abduct and torture a stranger for days before ultimately letting them go, or to fatally shoot a spouse in a fit of jealous rage? We speak to clinical psychologist Dr. Gary Bucato, co-author of the new book, 'The New Evil,' about how he determined what acts are more evil than others and why serial killers aren't all categorized the same way.

A&E True Crime talks to experts on Jeffrey Dahmer about his early life and what may have led to him becoming a serial killer.

Although cannibals have always existed throughout human history as a cure for overpopulation, a means of survival during a famine, or even a way to contend with grief, what's more rare are murderers who kill for sport and then devour their victims. We talk to Dr. Eric Hickey, a forensic psychologist, on why some killers eat their prey.