Paul Bernado and Karla Homolka were Canadian serial killers who attracted worldwide media attention when they were convicted of raping and murdering teenage girls, including Karla’s own sister, Tammy Homolka. These two serial killers are part of a fairly exclusive group of killers that killed as a couple. Paul Bernardo also admitted raping numerous other women over a period of years, and he eventually brought Karla into the mix. The question most people have when they hear of these murders, is why did Karla do it?