The repeal affects crimes committed on or after July 1 of this year, the Albuquerque Journal reported. New Mexico's two death row inmates and any other capital punishment cases arising from crimes committed prior to July 1 could still be executed.
Richardson, who had previously supported capital punishment, called his signing of the legislation the end of a "long, personal journey" for him.
"The sad truth is the wrong person can still be convicted in this day and age, and in cases where that conviction carries with it the ultimate sanction, we must have ultimate confidence -- I would say certitude -- that the system is without flaw or prejudice," Richardson said.
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