Most people are familiar with the big-name serial killers: Ted Bundy, Jeffrey Dahmer, and the ever-notorious Jack the Ripper. For those of us who can't get enough of that kind of thing, though... well, we have a tendency to stay up reading about lesser-known serial killers. Who needs sleep anyway? (Of course, whether you're happy that you know all about these gruesome crimes is an entirely different story; reasonable people probably prefer to go about their days without that kind of knowledge lurking in the back of their minds. Oh well.)
Serial killers, not to mention the true crime genre as a whole, have fascinated the public for ages, even though the odds of encountering one in real life are super slim. (Although maybe not as slim as you'd hope.) Maybe the appeal is in the adrenaline-pumping shock value, or pure psychological curiosity. As criminology professor Scott Bonn wrote in TIME last year, "The stories of real-life killers are often for adults what monster movies are for children."
No matter the reason, the fact remains that plenty of people are drawn to tales of serial murderers. If you know the famous cases inside and out (pardon the expression) and are looking for something new to learn, here are six serial killers you might not have come across before. But first, a word of warning: That doesn't mean they're any less terrifying.