The human race is different than any other kind of living creature on earth

The human race is different than any other kind of living creature on earth. It is mostly true that the majority of people can agree about something to a certain extent, but taking the life of another has always been considered the one of the worst of all crimes, one worthy of the harshest punishment available. Therefor one of the greatest moral dilemmas of our time raises many questions on weather or not it should be legal to taking the life on one person for killing another. Should taking the life of one who has taken the life of others be considered an available punishment?