What causes adults to kidnap children? The perpetrators range from serial rapists to parents trying to protect their sons and daughters.

There are countless theories about how Teamster boss Jimmy Hoffa died and where his body might be. Here's a look at the three most plausible and a few of the most bizarre.

In three decades as a forensic psychologist, Dr. Kris Mohandie has met one-on-one with some of the most violent men ever to grab headlines: Joseph Paul Franklin, Herb Mullin, Willie Woods and others. He talks to us about whether violent criminals are born or made.

Police have solved, or are close to solving, a number of cases that have been cold for decades. Investigators are using new technology and research techniques and re-examining leads that previous investigators may have ignored.

Could a strapping prep school athlete have been so afraid for his life that he strangled his sex partner as an act of self-defense during a late-night tryst? That was the question posed to jurors the winter of 1988 during the 'Preppy Killer' murder trial in New York City.

What happens to a young child who murders? The answer largely depends on whether they're tried as a juvenile or as an adult. And, in 33 of the 50 states, there's no minimum age for prosecuting child offenders, which means you can prosecute 3-year-olds.

Most people know Amber Alerts as child-abduction emergency notifications that help law enforcement find missing kids. But the tragic abduction and murder case behind the notorious alert system was never solved—and police are still looking for clues.

Before they're caught, serial killers often fly under-the-radar. But just because police and the public aren't aware of a killing spree, doesn't mean it isn't happening. We look at five unsolved serial killer cases, the murders connected to them and some of the information we do (and don't) know.

Lee Boyd Malvo, part of the D.C. Sniper duo who terrorized the D.C. area in a series of murders, is serving life in prison without parole. But Malvo, who was 17 at the time of the killing spree, may be up for parole in 2022 due to a new Virginia state law.

After escaping a Colorado jail in December 1977, serial killer Ted Bundy fled to Tallahassee, Florida, and went on a rampage, attacking and killing sleeping coeds at the Chi Omega sorority house at Florida State University. One of the survivors of that attack, Kathy Kleiner, spoke with us about getting over her mistrust of men and how authorities can help victims.