EWTN Catholic Q&A
Question from tjay on 11-29-2012:

Dear Father, That was a very good point, sent in, re Murder and not kill. Will remember that when defending the Faith. Also just to say God Bless you Father for all youre hard work/dedication thanks tjay

Answer by Fr. John Echert on 12-03-2012:

Thanks, TJ. Yes, the commandment prohibits murder, which is deliberate killing of the innocent. The commandment does not prohibit just war, self defense, justified capital punishment, etc.

Father Echert