Henry Lee Lucas and Ottis Toole traveled across 26 states in the 1970s, killing wherever they went. They preyed upon anyone they could find — including hitchhikers, sex workers, and migrants.

For Lucas and Toole, killing was just a way for the young couple to bond. They talked about it openly, comparing notes and giving each other tips.

Henry  Lucas later claimed that he coached Toole on how to get away with murder. “He was doing his crimes all one way,” Lucas said. “I started to correct him in his ways, in doing the crime where he wouldn’t leave information.”

But Lucas and Toole didn’t just kill. Often, they would rape and torture their victims before murdering them. And after their victims were dead, the couple would mutilate the bodies. Lucas later said that they didn’t feel the slightest amount of guilt for their actions. He even joked that he once crossed two state lines with someone’s severed head in the backseat.