As I said, the whole murder plot. You can re-kill (it's a bit weird) the victim, and then whack two others just to pocket some money. It's actually pretty nasty, if you're feeling really callus for some reason.
I don't know if people are actually that crazy, but considering killing one will also kill the other, it's probably meant so that you couldn't just kill the one that annoyed you while keeping the girl alive. Basically, don't expect some easy pussy, because she dies too if you rat them out.