"Human beings are mixture of good bad ego power jealous and all those BS. Technically if you are sure that you will be locked up for a life if you kill someone it will just increase more killings."

There is no evidence that this is true. In fact, statistics from States with the death penalty vs. States without, show that states with the death penalty have higher violent crime & murder rates than states without.

The death penalty does not act as a deterrent.