Murder: What is a murder?

A murder is the death of a person. It is supposed to be a sad moment but in certain countries this practice is allowed. They agree to take the life of people because of crime, murder, spy activity and many other reasons. In my opinion it's not human to kill people because life is the most precious thing we have, even if these people have killed other people they should be keept alive and stay till the end of their days in jail. For there exists a contradiction with people considered as evil but who become conscious of their fault, for example Stanley Tookie Williams III http://en.wikipedia.org/wiki/Tookie_williams