An expert in the psychology of school shooting perpetrators talks about who commits these heinous crimes.

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.

It's not uncommon for violence against women to reach a deadly peak on what some say is the most romantic day of the year.

Here are the complicated details of the case.

Researchers have found the vast majority of people who kill their families (familicide), are men with a history of violence toward their spouse and children. But what tips the scale from abuse to murder? And which men are most likely to kill? We spoke to a professor of forensic psychology for answers.

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

Dr. Mike Aamodt, forensic psychology professor at Radford University, on why female serial killers have declined over the years, why there was a big jump in serial killings in the U.S. between the 1960s and 1980s and his most surprising finding in his research of serial killers.

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.

Why do so many killers—Jeffrey Dahmer, Ted Bundy and David Berkowitz to name a few—abuse animals before targeting people? An expert provides insights on how the two behaviors are linked.