I'm very much against the death penalty. Even if we know for certain, 100% that the accused is actually guilty of say, murder, I think it is still wrong to kill someone. After all, Isn't that why we arrested, tried and convicted them?
If it is illegal for private citizens to murder, then it should be illegal for the state to murder as well. I don't see it as justifiable homicide--self defense. After all, the state has the person in custody.
I also believe that prisons should be humane, provide decent shelter, food, medical care including mental health and addiction, access to education and job training, etc. Rape should not be part of the sentence.