There's nothing more frightening than couples coming together over their shared love of murder. These killer duos, who range from thrill killers to sadomasochists, all committed atrocious crimes that are still hard to read about today. But probably the most baffling thing about these pairs is the role women often played in these cases. For some, they were victimized followers who were simply "taking orders." For others, they were willing accomplices who killed for love and devotion to their husbands. Below, seven killer couples and the crimes that made them infamous.