Electric chair and be done with it. The world is better without people like this. No forgiveness. But there will be some lawyer who defends his actions claiming mental illness, therefore, it's not completely his fault since he was in a different state of mind. Throw him into a cell and use him as a experiment. Let's see how long it takes for him to die without food and water. For this father to be okay with killing his daughter who's a child, I cant imagine what other skeletons he's hiding in the closet.