Killing People who kill

Killing people who kill people - Wouldn't you think that most of, if not all, try to teach our kids that it is wrong to kill other people. Whether you are a religious person or an atheist or an agnostic, most of us take it as a core moral that human life is important. A few years back I brought my (state the name and age of the child, e.g., "my twelve-year-old son, Ted") down here to hear me argue for another man's life. On the way down the boy asked me, "Dad, why do we kill people who kill people to show that killing is wrong?" That question and the answer to it goes to the core of what we are doing here today. Why do we kill people to show that killing is wrong?
Yesterday, that same boy, now (indicate the current age) asked me, "Are they going to kill (name the defendant)? I said, "I don't know."