Just to be clear I would posit that:

Yes, all people have the right to life, and I would have to agree that all murderers are people, therefore deserving the right to life. They are also responsible for their actions and have to live with those consequences. The social paradigm will determine the ramifications and punishment for those actions, and whether or not one agrees with the determinations made we have to make a decision: Does society have the right to negate life as that punishment, or is this right to life inviolate?

What happens when the ‘murderer’, as in the case of Parkland which was just in the news last week, we have a young man who shot and killed 17 children? The issue of mental competence is somewhat moot since I believe that anyone who kills is to some degree damaged goods. What do you do with such an inhuman human? What if it were your child, your wife, your mother or your siblings? Would that change the determination?