A Texas inmate convicted of murdering the son of a prominent lawyer during a robbery was executed Wednesday night after losing an eleventh-hour appeal to the U.S. Supreme Court.

Mauriceo Brown, 31, apologized to the victim's family and spoke reassuringly to his own family before being injected with a lethal dose of drugs. He was pronounced dead at 6:47 p.m.

Brown, who confessed to the killing but later tried to recant his confession, apologized to two brothers of the victim, Michael LaHood Jr.

Brown told the men, who were watching through a window, that he was "sorry you lost a brother, a loved one and friend."

To his mother and two siblings who also witnessed the execution, Brown said, "Keep your heads up and know that I will be in a better place."

Brown's mother wailed and collapsed to the floor as the drugs took effect, and she was led from the witness area.

Brown was the 15th inmate executed in Texas this year.

A San Antonio jury convicted Brown, with co-defendant Kenneth Foster, of capital murder for the August 1996 shooting death of LaHood, a 25-year-old law student.

Prosecutors said the pair, with two other men, had been drinking, doing drugs and carousing the city committing a series of burglaries.

Following a sentencing hearing, where a jury heard about the pair's affiliations with street gangs, the two were sentenced to death in May 1997.

Another defendant, Julius Steen, who testified in exchange for a lighter sentence on a charge of aggravated robbery, told the jury that he saw Brown point a handgun at LaHood and demand his wallet during a confrontation in front of the home where LaHood and his parents lived.

LaHood died instantly from a single gunshot wound to the head that was fired at close range.

Brown also took the stand in his defense and testified that he shot LaHood because he thought he was going to shoot him first.

Since his conviction, however, Brown had denied that he was the shooter, claiming that his friends threatened him into confessing.

In the weeks before Brown's scheduled execution, his appellate lawyer, David Sergi, asked to perform DNA testing on the clothing that the four men were wearing the night of the shooting.

Sergi argued that blood spatter on friend Dwayne Dillard's clothes would prove that he was the shooter, but a criminal appeals court judge rejected the request.

Dillard, who is serving a life sentence for an unrelated murder, was never charged in the LaHood shooting. But in the weeks leading up to Brown's execution, he came forward to provide information to support his former friend.

In an affidavit, Dillard claims that the group did not attempt to rob LaHood or his friend, a factor that determined whether the murder was a capital crime.

The third co-defendant in the case, Steen, also filed an affidavit stating that there was no intention to commit a robbery that night, contrary to what he said at trial.

A prosecutor from the trial of Brown and Foster told the Associated Press that the new claims were "preposterous."

"He has absolutely no credibility. Any court could see he has zip," said Mike Ramos, who was a Bexar County assistant district attorney in 1997.

In an interview with CourtTVnews.com, Brown said he regretted confessing to the crime.

"I regret it for the fact that I didn't put more faith in the man upstairs to look over my family ... But, you know, when you're in the streets and you've been around these people for a while, you kind of know that it could happen," Brown said, one week before his scheduled execution. "I knew that I got into this for all the wrong reasons, and it just wasn't me. I should've stayed with basketball."

The Associated Press contributed to this report.