An inmate who once bragged about the headlines generated by the carjacking and murder that sent him to death row will be noted in Texas history for a different reason: Yokamon Hearn will be the first prisoner executed under the state's new single-drug procedure.

Hearn, 33, is set to die Wednesday for the March 1998 fatal shooting of Frank Meziere, a 23-year-old suburban Dallas stockbroker who was abducted at gunpoint while he cleaned his car at a self-service car wash in Dallas. Meziere was driven to an industrial area and shot 10 times before his body was dumped on the side of a road.

Hearn will be the sixth Texas prisoner executed this year, but the first since the Texas Department of Criminal Justice announced its switch to single-drug lethal injections amid a drug shortage that has left states scrambling for acceptable alternatives.

Texas said last week it will now use a single dose of pentobarbital, instead of using the sedative in combination with two other drugs. Ohio became the first state a year ago to use a single drug, and several other states have since made the switch. Courts have upheld the practice, despite death penalty opponents' claims that it prisoners take longer to die with a single drug.

Hearn has not made an appeal based on method of execution or claims of innocence. Instead, his appeals have focused on his mental capacity, the competence of his attorneys and whether recent lower federal court rulings improperly blocked his current lawyers from pursuing appeals.

In 2004, a federal court spared Hearn less than an hour before he could have been taken to the Huntsville death chamber so that it could consider arguments that he was mentally impaired and therefore ineligible for the death penalty.

That appeal subsequently was rejected, and attorneys more recently told the U.S. Supreme Court that while tests show Hearn's IQ is considerably higher than levels determining mental impairment, he suffers from a fetal alcohol disorder that should disqualify him from execution.

Jason January, the former Dallas County assistant district attorney who prosecuted Hearn for capital murder, dismissed claims that Hearn was disabled.

"He was quite capable of functioning and figuring out how to rob people," January said this week.

Hearn, known to his friends as "Yogi," was 19 at the time of Meziere's murder and had a lengthy record that included burglary, robbery, assault, sexual assault and weapons possession.

A security camera video at a convenience store next to the car wash captured images of Hearn with two other Dallas men and a woman from Oklahoma City. They had been out looking for someone to carjack, authorities said.

According to trial testimony, Hearn and Delvin Diles forced Meziere into the stockbroker's car, and Hearn drove it to an area near Dallas' wastewater treatment plant. The two others, Dwight Burley and Teresa Shirley, followed in a second car.

Meziere, from Plano, was shot with a stolen, assault-style rifle and then with a .22-caliber pistol. Shirley testified that Hearn shot Meziere with the rifle and then continued to fire after he hit the ground. Diles then shot him with the pistol.

She also testified that Hearn later waved around a newspaper account of the crime and was pleased it said Meziere had been shot in the head, or "domed" in street slang. According to The Dallas Morning News, Hearn told her: "I told you I domed him. I told you. I told you."

Diles, 19 at the time, pleaded guilty and received consecutive life terms for Meziere's death and an unrelated aggravated robbery. Shirley, 19, and Burley, then 20, pleaded guilty to aggravated robbery and received 10-year prison sentences.

Hearn would be the 483rd inmate executed since Texas resumed carrying out capital punishment in 1982. He is among at least nine men with execution dates in the coming months.