Capital Punishment

Every year thousands of people are executed; those who have been convicted of vicious crimes are sentenced to death whether its by lethal injection, hanging, electric chair or by any other justifiable means. What gives us the right to say who gets to die and who gets to live? Whatever happened to the statement "thou shall not kill" Who are we to judge? People make mistakes in judgment everyday what makes the courts any different? Do you agree that people that have been convicted of high level crimes should be sentenced to death? Is it justified?