Homolka, unfortunately, was as cunning a liar as she was evil. She conned the Canadian authorities into believing her story that she was terrorized by her husband (Paul Berarndo, IIRC) and was forced to participate in the killings. It wasn’t until the ink was dry on the plea agreement that the videotape was uncovered showing that Carla was not only an active participant in the crimes, she was if anything, more into the deed than hubby. By that time, there was no way to undo the deal, and she got out after a few years while hubby is doing life without parole.
Homolka is pure evil. IIFC her younger sister was one of her victims. And you are right; she conned authorities into believing her story. That, and the fact that they wanted to convict Bernardo so badly they just cut her a deal. At least that b**tard is where he belongs.