By David Beasley
ATLANTA (Reuters) - The U.S. Supreme Court removed one legal roadblock to Alabama's planned execution on Thursday of a man convicted of murdering a police officer and later rejected a last-minute appeal to spare his life, allowing the lethal injection to proceed.
The high court first lifted a halt imposed by a lower court over concerns about one of the drugs used in the state's lethal injection mix.
Its decision came a few hours before Alabama planned to execute 40-year-old Torrey McNabb for the 1997 murder of Montgomery police officer Anderson Gordon. Gordon was shot five times as he sat in his patrol cruiser, according to court records.
The execution had been scheduled for 6 p.m., but was delayed as lawyers for the death-row inmate filed a last-minute petition to spare his life.
After the filing, the Supreme Court granted a stay to consider the latest petition. But it later denied that appeal, allowing the execution to go ahead.
On Monday, a federal judge in Alabama stayed McNabb's execution to allow him time to challenge the state's use of the drug midazolam, a valium-like sedative used in executions in Oklahoma and Arizona where inmates were seen by witnesses as writhing in pain on death chamber gurneys.
Lawyers for death-row inmates have argued the drug cannot achieve the level of unconsciousness required for surgery, making it unsuitable for executions.
Lawyers for the state on Wednesday asked the Supreme Court to lift the stay, arguing that midazolam puts a person into a deep coma.
In its order on Thursday, the Supreme Court said that the lower court abused its discretion in ordering the stay because it did not find that McNabb had "a significant possibility of success on the merits," the order said.
(Reporting by David Beasley; Additional reporting by Jon Herskovitz in Austin, Texas; Writing by Keith Coffman; Editing by Patrick Enright and Peter Cooney)