Is the death penalty a good way to punish those who murder another human being?

Yes and no. Yes, because what they have done to another person is now being done unto themselves; otherwise known as the "Eye for an eye" philosophy. Some can argue no because it is inhumane or cruel to kill another person. Also, one could also argue that a person can change or that it is a sin to kill someone that has a chance to repent or to apologize honestly for their actions.