By Peggy Gargis
BIRMINGHAM, Ala (Reuters) - A man convicted of the 1994 execution-style shooting death of a store clerk in Alabama is scheduled to be put to death on Thursday by lethal injection in what would be the third U.S. execution this week.
The execution of Derrick O'Neal Mason, 37, is set for 6 p.m. local time at Holman Correctional Facility in Atmore.
Mason has been on death row for 16 years. His execution, if carried out, would be the third this week in the U.S., following two high-profile cases in Georgia and Texas.
In a case that drew international attention, Troy Davis was put to death in Georgia late Wednesday for the murder of a police officer, despite claims by his advocates that he may have been innocent.
Texas on Wednesday executed a white supremacist convicted of helping to kill a black man by dragging him behind a truck, in a case that sparked a wave of hate crime laws.
Mason's execution would be Alabama's fifth this year. Thirty-five inmates have been put to death in the U.S. in 2011.
He was convicted of killing 25-year-old Angela Cagle during the attempted robbery of a convenience store in Huntsville, Alabama. Authorities said he forced Cagle to strip naked and shot her twice in the face at close range.
Alabama Governor Robert Bentley on Wednesday said he would not intervene to halt the execution.
Earlier this month, the judge who sentenced Mason to death asked Bentley to spare the inmate's life.
In a September 8 letter, Judge Loyd Little Jr. did not dispute that Mason "terrorized the victim." But he wrote that if he had tried the case as a more experienced jurist, he would have sentenced Mason to life without the possibility of parole.
Neither Little nor the defense team had any experience in capital murder cases before the Mason trial, the judge said.
Little said that compared to other cases he presided over later, this one was not as "heinous, atrocious, or cruel."
The judge wrote that without that aggravating factor to consider, the jury "would have recommended life without parole and I would have followed that recommendation."
In court filings, appellate attorneys for Mason argued that his defense team omitted key mitigating factors during the sentencing phase, including his claim that he smoked a marijuana cigarette the night of the crime that, unknown to him, was laced with psychoactive substances.
In a court filing to the state Supreme Court on Wednesday, Alabama Attorney General Luther Strange quoted the judge's sentencing remarks about the heinous nature of the crime.
Strange concluded that the judge's "change of heart is not a basis for this court to grant Mason's petition for a stay of execution."
(Editing by Colleen Jenkins and Greg McCune)