Serial killers are real-life nightmares.

Leslie Van Houten was 19 when she killed Leno and Rosemary LaBianca. Should she go free?

Nikolai Dzhumagaliev dismembered and consumed at least seven victims.

She and her best friend met the killer at a local pub one night...

The murderous duo killed at least nine people together between their meeting in 1969 and their eventual arrest in 1994.

The director believes he interrogated the man responsible...

In each of his victims, he sought someone who would never leave.

She's one of the most prolific female serial killers of all time, with an estimated 36 victims.

What's it like to communicate with the world's most depraved murderers?

There's something wrong with Jeffrey...

Did Holmes' reign of terror reach England?

Some nurses shouldn't be trusted...

This hotel hid secrets and bodies within its walls.

This deadly pair from 18th century America left a bloody trail across the frontier as they slaughtered men, women, and children to satisfy their bloodlust.

Peek inside their dark minds...

The semester from hell doesn’t even begin to describe it for these students.

Can the Disney heartthrob make the transition to cold-blooded killer?

He seemed have everything going for him ... but darkness lurked beneath the surface.

Don't let him in.

Did the sadistic "Murder Castle" serial killer fake his own death in 1896?

These sadistic killers shocked the world with their horrific crimes.