Money for murder?

In my mind I would love to be able to kill someone to get the money because afterall, i'm guarantee that its clean and I wont ever get caught. But in my heart it say thats a NO NO. So errrr this is a hard decision but I think I would most likely not do it. I probably wont be able to live with myself if I do kill that person. BUT!!!! if the person i'm killing is a serial killer or rapist then i MIGHT do it. But even so, I doubt that I will. I just wouldn't be able to sleep at night. I might go insane afterward and commit suicide? lol