For Jeffrey Dahmer, it was watching certain movies. Dennis Rader, known as the BTK Killer, set the mood by pretending he was a spy. Ted Bundy liked drinking alcohol before some of his slayings. Not every serial killer has a signature routine, but some of them do engage in some sort of ritual or preparation before a killing.

Read an excerpt from Michael Arntfield's true-crime book, 'Monster City,' about serial killer Tom Steeples, a computer store owner who found two of his victims, a newly married couple, at a dive bar's amateur showcase.

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.

Peter Vronsky, author and investigative historian, speaks with us about ancient killers, the influence of technology on crime and how, in 100 years, the Long Island Serial Killer could be the new Jack the Ripper.

Read an excerpt from FBI Special Agent Jeffrey L. Rinek's book, 'In the Name of the Children,' about his interrogation of Yosemite Killer Cary Stayner over pizza.

Some studies claim male sexual-homicide offenders over age 50 are rare—murders committed by them account for only 0.5 percent of sexual homicides in the U.S.—which may be due to steep declines in their testosterone levels. But could a decline in testosterone really put a halt to a killer's murderous spree?

Gary Leon Ridgway, who raped and murdered more than 49 women, was obsessed with deviant sex and visiting prostitutes. This, combined with his aggression and violence, were significant driving forces behind his murderous actions, says Mary Ellen O'Toole, a retired FBI senior profiler who interviewed Ridgway.

Read an excerpt from Anne K. Howard's book, 'His Garden: Conversations with a Serial Killer' where William Devin Howell gives details about how he murdered and disposed of some of his victims.

Tricia Griffith, who runs the web forum Websleuths, talks to A&E True Crime about her close encounter with Ted Bundy, how the online community dug into the Casey Anthony case and why she believes police should let amateur detectives help investigations.

A&E True Crime talks to retired FBI profiler Dr. Mary Ellen O'Toole about serial killers, like Ted Bundy and the Toolbox Killers, who had well-defined victim preferences.