AUSTIN, Texas (Reuters) - A Dallas man who was convicted of murdering his ex-girlfriend in 1999 while he was out on parole was executed on Tuesday after the U.S. Supreme Court rejected a last-minute appeal, prison officials said.

Deathrow inmate William Rayford, 64, is shown in this 2010 booking photo in Huntsville, Texas, provided January 29, 2018. Texas Department of Criminal Justice/Handout via REUTERS

William Rayford, 64, was pronounced dead at 8:48 p.m. central time (9:48 p.m. eastern), said Texas prison spokesman Jason Clark. He was sentenced to death for beating and strangling former girlfriend Carol Hall, 44.

Rayford apologized to the victim’s family and asked for them to forgive him in his final words, according to Clark.

“I’m sorry, it has been bothering me for a long time. So I now pray and I will keep you all in my prayers. I hope you find it in your heart to forgive me. I’m sorry,” Rayford said, according to Clark.

Rayford had served eight years of a 23-year sentence for killing his wife in 1986 when he was released on parole in 1994, prison records showed.

His appellate attorneys had launched a late appeal with the Supreme Court, saying the lawyers who represented him at the punishment phase introduced prejudicial racial elements and failed to provide adequate counsel. Rayford is black.

“Mr. Rayford ... received a death sentence after his trial attorney elicited evidence that a person’s race is a factor in their likelihood of committing assaults while in prison,” they wrote in their appeal, adding that a link between race and prison assaults did not exist.

Lawyers for Texas contend that Rayford did not complain until one week before his scheduled execution that his trial counsel was ineffective.

They said blood taken from Rayford’s lip, head and neck at the time of the killing matched Hall’s DNA.

Prosecutors said Rayford had a key to Hall’s home and entered on the day of the murder. He then got into an argument with his former girlfriend.

When Hall’s then 12-year-old son came to see what was happening, Rayford stabbed the boy in the back and Hall fled for safety, prosecutors said.

The boy, who survived, went to a neighbor’s house and the neighbor called police, they said.

Rayford caught Hall and then beat her to death, dumping her body in a drainage pipe, prosecutors said. Rayford was captured in Hall’s backyard about an hour after police arrived. He was wet and had bloodstains on his clothes, they said.