Just goes to show, you're better off letting the law deal with it. You won't enjoy it and you may not agree with the court, but at least you won't be in prison as well.
This seems like the safest course of action. Just be careful to watch out for those stairs, they can come out of no where.
Also, sucks for the whole family, and i think this guy deserves to spend the rest of his life in prison.
Im sorry but if someone raped my sister, cousin, niece or any woman for that matter and I had the chance to do this I would not aim lower but higher. I love my family and something like this would ruin their life forever so I would take the chance and stay in prison for the rest of my life so this bastard wont get out in seven years and do it to someone else that is defenseless.