JC Ferguson, commander of communications training for Austin-Travis County Emergency Medical Services—which is featured on 'Nightwatch Nation'—speaks with A&E True Crime about how 911 call takers and dispatchers handle the stress of responding to calls about violent crimes.

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?

For over a century, electricity has been used as the ultimate punishment on criminals who've gone violently astray of the law. Soon, it may be used to rehabilitate them. In July 2018, a new study was released suggesting that running electrical currents through people's brains reduces their desire to commit acts of aggression.

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.

Although the majority of murders are committed by someone the victim knows personally, killers are taking advantage of the popularity of social media to seek out strangers on Facebook, Craigslist, Tinder, Grindr and various dating sites.

A&E True Crime spoke to the Greene County (Missouri) Sheriff's Office officer about working with K-9 Lor and a few truths about police dogs that he'd like the world to know.

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.

In 1991, Miguel Angel Martinez,17, Manuel 'Milo' Flores,17, and Miguel Angel Venegas, Jr.,16, each played a role in a triple axe-and-knife murder that rocked the small city of Laredo, Texas. The motivation behind the crime remains a mystery. Martinez and Venegas tell their stories in 'I Am a Killer,' available on Netflix. 

Move over fingerprints—an exciting new field of forensics has emerged: DNA phenotyping, where investigators interpret DNA left behind at a crime scene to make predictions about what the perpetrator might look like. We spoke with Ellen Greytak, a bioinformatics expert, to learn more about the use and limitations of this new science.

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.