Is Murder Ever Justifiable?

I think murder is justifiable some of the time. The person who was murdered could've been a sick twisted person, that beat his family, or raped his wife, and it drives people to murder that person for putting them under physical and emotional depression. Most time murder is not justified in many situations like if a kid steals candy from a store, they shouldn't get shot for it. But in most cases such as killing, rape, physical/mental abuse, its most likely that some would could and sometimes should get murdered.