Convicted killer Gayland Bradford was executed Wednesday for the $7 robbery-slaying of a Dallas grocery store security guard almost 23 years ago.

In a final statement, Bradford, 42, thanked friends for being with him "through thick and thin."

"I am at peace," he said. "We have no worries, just as I have no more worries. To the victim's family, may you be at peace also."

As the lethal drugs took effect, he gasped a couple of times, then began snoring, each breath progressively fainter. Nine minutes later, at 6:25 p.m., he was pronounced dead.

Bradford already was on parole for a robbery conviction when he was arrested for gunning down 29-year-old Brian Williams four days after Christmas in 1988. The shooting came on Williams' second day on the job at the market a few miles south of downtown Dallas.

Williams' mother and brother were among the people in the death chamber, watching through a window just a few feet from Bradford.

"We have no anger towards Mr. Bradford and forgive him of his crime against our family," Williams' brother, Gregory, said in a statement released following the punishment. "We now turn our thoughts and prayers to Mr. Bradford's family and friends and pray that God will give them the strength, comfort and understanding as they now grieve the loss of their loved one."

The U.S. Supreme Court last week refused to reconsider an appeal they rejected earlier, clearing the way for Bradford to become the fourth Texas prisoner executed this year. Three more lethal injections are set for this month in the nation's busiest capital punishment state.