Opponents of the Death Penalty pt 1

Many people in society oppose the death penalty. This is due to them seeing the capital punishment as a denial of Human Rights, here is a quote from a popular website called Amnesty International:

"The death penalty is the ultimate denial of human rights. It is the premeditated and cold-blooded killing of a human being by the state. This cruel, inhuman and degrading punishment is done in the name of justice.
It violates the right to life as proclaimed in the Universal Declaration of Human Rights.
Amnesty International opposes the death penalty in all cases without exception regardless of the nature of the crime, the characteristics of the offender, or the method used by the state to kill the prisoner."

The Quote is factually right, as said before  The Anesthetic of the Injection is often not properly distributed. But where this website is wrong, or should look over is where they say it is a denial of human rights. By not applying the Capital Punishment, morally the Right of life is being denies to the victims of the killers, by not getting their retribution, these victims would have died with no justice being done. The most current thread, Terrorism is infamous due to the amount of killing they both execute and plan, these cases and caught suspects should be put on the deathbed as well. The government not killing a killer is a denial of human rights as well.
Keith States that There is no proven fact that jail deters a human more than death. while another document of the same author states that Death is a better punishment. these two opinions differ and cannot be proven as said in the first article, but the punishment is determined by the Punished. putting a gang leader in a jail where his minions are stored in will not change his state of mind, but a normal killer with no affiliations will think about his time in jail and will change his state of mind.