George Kent Wallace, who pleaded guilty in 1991 to killing two Arkansas teenagers in LeFlore County, is scheduled to die about 9 p.m. Thursday in the H Unit at the State Penitentiary in McAlester.
Future executions could be at 9 p.m. or earlier, Corrections Department spokesman Jerry Massie said. Before, executions were shortly after 12:01 a.m.
"It would be more convenient for the family members of the victims," he said of the new schedule. "Many times they would drive home afterward."
The time set for Mr. Wallace's execution worked best for corrections officials instead of other times that evening, Mr. Massie said.
With one exception, executions have been just after midnight since the state reinstituted the death penalty in 1976.
Olan Randle Robison was executed about 6 a.m. March 13, 1992, in keeping with a judge's order, Mr. Massie said.
Midnight was chosen at first so prison officials could focus on conducting executions with fewer distractions, he said.
"We also felt like if something happened we had 24 hours in that same day to carry it out," Mr. Massie said.
Any delays that push evening executions past midnight might force the state to seek another execution date or to pursue a change in the death warrant to provide a 24-hour window, he said.
Texas began executing death row inmates just after 6 p.m. in 1996, said Larry Fitzgerald, a spokesman for the Texas Department of Criminal Justice.
The state adopted 6 p.m. instead of midnight so defense attorneys could reach judges for possible stays while courts were in session, he said.
The new time was also more convenient for the staffers of the governor, the state attorney general and corrections officials, Mr. Fitzgerald said.
Texas law says executions cannot start before 6 p.m. and must be done by midnight or the inmate automatically gets a 30-day stay, he said.
Mr. Wallace, 59, was sentenced to death for the murders of William Von Eric Domer, 15, of Fort Smith, Ark., and Mark Anthony McLauglin, 14, of Van Buren, Ark. The boys' bodies were found at different times in a pond outside Pocola near the Arkansas line.
William was found Feb. 22, 1987. Mark was discovered Nov. 12, 1990, said Gerald Adams, a spokesman for Oklahoma Attorney General Drew Edmondson.
Mr. Wallace is a former resident of Fort Smith, Ark., and Pfafftown, N.C.
The Wallace execution would be the 30th since Oklahoma reinstated the death penalty in 1977 and mandated death by lethal injection instead of the electric chair.
Oklahoma's executions have become more frequent, with 10 dying so far in 2000 compared with six in all of 1999.
Texas has killed 26 this year and 225 since reinstating the death penalty in 1978, Mr. Fitzgerald said.