You guys did lose some je ne sais quoi with the New Testament stuff.
Sometimes people just owe you blood.
I don't know how people can forgive in situations like this either. I don't believe I could. I am an eye for an eye person.
We do have the example of Christ asking for forgiveness for the people for the people who nailed him to a cross.
We actually talked about this at Sunday School recently. I wanted to know if people should forgive even in the absence of repentance. I didn't get a hard and fast rule as an answer, but my teacher discussed how he was eventually able to forgive his horrible ex-wife. It allowed him get over being eaten up with anger and becoming a miserable person.
However, forgiveness doesn't negate any judicial punishments. Ideally, these murderers would be executed.