Jamaal Howard, 46, was executed at the Huntsville Unit in Texas on Wednesday after being convicted of murdering convenience store clerk Vickie Swartout during a 2000 robbery. The Texas Department of Criminal Justice said Howard was pronounced dead at 8:03 p.m. after receiving a dose of pentobarbital.

Howard was sentenced to death in April 2001 for killing Swartout, 42, at a convenience store in Silsbee on May 12, 2000. Howard was 20 years old at the time of the crime.

According to court records, Howard entered a secured office area of the store and shot Swartout in the chest. He then took $114 from the cash register and reached over the dying clerk to take a carton of cigarettes before fleeing. Surveillance cameras captured the robbery and shooting.

In his final statement, Howard apologized to Swartout's family and asked them for forgiveness.

“I wish for your forgiveness. I’m sorry for what happened,” Howard said.

He also thanked members of his family and others who had supported him throughout his incarceration, telling them that he loved them. Howard concluded his statement by telling the warden that he was ready.

As the pentobarbital took effect, Howard took several breaths and began gasping and making snoring sounds. He coughed before the sounds gradually became quieter. His movement stopped within roughly 30 seconds, and he was pronounced dead 19 minutes later.

The execution came after Howard's attorneys sought to delay it, pointing to the recent failed execution attempt of Christa Pike in Tennessee. They argued that pentobarbital could pose similar risks and also maintained that Howard was intellectually disabled.

Pike's execution attempt on Sept. 30 at Riverbend Maximum Security Institution in Nashville was halted after she remained alive following two rounds of pentobarbital. She was eventually transported to a hospital for treatment.

Pike's attorneys said Tuesday that she remained conscious and able to speak but continued to require critical medical care. They said the failed execution caused severe damage to her arms and that she faces a lengthy recovery.

Howard's execution marked the first in the United States since Pike's failed lethal-injection attempt. Unlike Pike's execution, Texas officials completed Howard's execution using pentobarbital, and he was pronounced dead shortly afterward.