Forensic psychologist, Dr. Katherine Ramsland, tells A&E True Crime about her over a decade-long correspondence with BTK and how she got into the mind of the prolific serial killer.

Criminologist Dr. Scott Bonn deconstructs Dennis Rader's 'Factor X', the blamed culprit for why a devout Lutheran and father was driven to commit 10 murders between 1974 to 1991.

Investigative historian Peter Vronsky explains how Edmund Kemper, Ted Bundy, Jeffrey Dahmer and others reached celebrity status during the 'Golden Age' of American serial killing.

Over nearly two decades, Dennis Rader murdered at least 10 people in the Wichita, Kansas area under the pseudonym BTK ('Bind, Torture, Kill'). But despite his repeated taunts to the police and media, investigators were unable to hone in on a suspect.

A&E True Crime takes a closer look at the lives of serial killers Dennis Rader, Randy Kraft and Richard Cottingham, whose seemingly normal childhoods gave way to unspeakable cruelty.

Kerri Rawson, daughter of Dennis Rader, otherwise known as serial killer BTK, talks to A&E True Crime about her struggle to reconcile the man who raised her with the one who, for years, terrorized her hometown of Wichita, Kansas.

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?

Serial killers often live fairly ordinary lives with normal employment, enabling them to blend in with colleagues. Their legitimate jobs also offer them one more key perk: an opportunity to help carry out or conceal their crimes, according to experts.

Killers who leave notes at crime scenes or mail missives to police and the press take a big risk. Read stories and watch videos about eight murderers who just had to put it in writing.