Doug Giles makes a compelling case for Christians to support the death penalty. Here are two relevant paragraphs:
If I were the toad that took the life of the Lundsford or the Lunde girl, the right "Christian" thing to do to show that I "love myself" would be to confess to the crime, give myself up to the police, seek forgiveness from Almighty God (and beg it from all family members of my victim) and then ask to be deleted. I’m not part of the Kool-Aid drinkers who think "loving your enemy as one loves himself" excludes punishing to death the perpetrator—whether it’s someone else or me.
If I did such a damnable act and really loved myself, then I would dutifully subject my person to punishment—in particular to death. Yes, if I really loved myself, I would bear responsibility for my actions, which means that I would insist on taking one for the team by leaving this planet, via execution, because I have just violently offended the sensibility of the entire human collective.