While there’s no one-size-fits-all profile for the type of women who would fall for a serial killer, they’ve usually experienced troubled childhoods, said Sheila Isenberg, an English professor and the author of Women Who Love Men Who Kill.

“Without exception, the women I interviewed for my book had all been involved in early abusive relationships,” Isenberg said. “Their families, first boyfriends, husbands or someone else had abused them either sexually, physically, emotionally.”

According to Isenberg, getting involved with an imprisoned criminal gives the women some semblance of power.

“It’s a chance to be in control, often for the first time in their lives,” Isenberg told HuffPost. “They make the decisions, they are the ones with the freedom to come and go.”

It may seem counterintuitive, but “becoming involved with a violent convicted murderer feels safe for a woman who’s had an abusive past,” the writer said. “He’s behind bars; she’s not.”