"When someone has cancer, they go to the doctor and the tumor is removed. Now, does the doctor place the tumor in a Petri dish, wait for the tumor to become nice cells and then put them back in the patient? No, he destroys them. Murderers are cancers on the body of our society. Once convicted, they should be executed."
This makes complete sense to me. Obviously, we need to be sure - not just beyond a reasonable doubt - but 100% sure. And the crime must warrant death - self defense, accidents, negligence don't qualify in my opinion. But violent, pre-meditated, in the commission of a crime, or of a police officer - for these things justice should be swift and certain. While I wouldn't deliberately try to make the killers suffer during the execution, if it happened at times...I wouldn't cry, either.