HUNTSVILLE, Texas (AP) Condemned prisoner Frank Moore was headed to the Texas death chamber Wednesday night for a double killing exactly 15 years ago in San Antonio.

Moore, 47, insisted he shot Samuel Boyd, 23, and Patrick Clark, 15, in self-defense as they were trying to run him down outside a bar where they had been involved in an earlier altercation. Attorneys were in the federal courts, including the U.S. Supreme Court, with last-day appeals seeking a reprieve after obtaining affidavits recently from three eyewitnesses who backed Moore's self-defense claims.

Moore would be the second prisoner executed this year in the nation's most active death penalty state. Another Texas inmate was set to die Thursday, and three more were set for next week.

Testimony showed Boyd and Clark got into a fight with Moore and his half-brother, that Boyd and Clark then got into a car and tried to run them over. One of Moore's friends tossed him a rifle from the trunk of a nearby car and he opened fire.

"That's the whole thing the whole basis of this," Moore said last week from death row. "It had nothing to do with gangs or drugs. They were trying to rob and kill me."

Jim Wheat, one of Moore's prosecutors, recalled that Moore "blew them away."

"Clearly, he was the guy who felt in control and they crossed the line with him," Wheat said.

Moore had an extensive criminal record when charged with capital murder. He denied being an active member of several violent gangs, as authorities contended. According to court documents, Moore belonged to the East Terrace Gangsters, who took their name from a San Antonio public housing project; was a "sergeant-at-arms" for the Black Panthers, responsible for obtaining, hiding and distributing weapons; and had been a member of the Crips gang since he was 14 in California.

Moore said from prison his Crips involvement was a way of life for teens in his neighborhood, but that he long had put that behind him.

Moore first went to prison in 1984 on a five-year sentence for attempted murder. He was released on mandatory supervision less than two years later, returned to prison as a violator within nine months, then was discharged in 1989.

In 1991, he got an eight-year term for cocaine possession but was paroled after just four months. He returned to prison in five months with a 20-year sentence for delivery of cocaine but was paroled after serving just over two years. The double slaying occurred about 10 weeks later.

Pat Moran, Moore's trial lawyer, said Moore ran the club and the two victims wanted to take over.

"They had gone around and talked how they were going to lure Frank outside and do something to him," Moran recalled. "It was going to be a good old-fashioned hostile takeover at the cost of Frank's life.

"There has never been any doubt in my mind if was self-defense. The problem was Frank was a multiple-convicted felon and Frank couldn't be around firearms. There was no way to put on a defense to explain why those two kids who thought they were getting the drop on Frank walked into such an effective and efficient execution."

The Texas Court of Criminal Appeals threw out Moore's first conviction in 1998 because jurors weren't allowed to consider lesser charges of voluntary manslaughter and murder. He was retried the following year and convicted and condemned again.

When Moore was arrested three days after the slayings, he'd just been arrested for an unrelated crime and was found carrying a revolver in his waistband. Less than a month before the killings, he was arrested for selling crack cocaine to an undercover officer.

On Thursday, Reginald Perkins, 53, was set to follow Moore to the death chamber for the slaying of his stepmother in Fort Worth eight years ago.

Copyright 2009 The Associated Press.