A onetime "drugged-out street punk" who stabbed a man to death during a bungled robbery attempt 12 years ago was executed by injection early Wednesday.

Milton Griffin-El, 37, smiled as the doses were administered at the Potosi Correctional Center. A few minutes earlier, he asked the families of his victims and God to forgive him.Griffin-El's last words were, "Tell my son and family that I love them." He also asked the families of his victims to forgive him.