A federal appeals court ruled Tuesday that a condemned inmate waited too long to challenge Georgia's method of execution, lethal injection.

Samuel David Crowe is to be executed Thursday for a murder he admitted to 20 years ago, the slaying of Joseph V. Pala, manager of Wikes Lumber Co. in Douglasville. Crowe would be the second person put to death in Georgia in 16 days.

The 11th U.S. Circuit Court of Appeals rejected Crowe's pleas for a stay, noting that his challenge to lethal injection "was filed several years beyond the applicable two-year statute of limitations."

The judges wrote he could have raised his concerns earlier "at such a time as to allow consideration of the merits without required entry of a stay."

Crowe could be the third person in the nation put to death by lethal injection since the U.S. Supreme Court ruled in April that the use of the three-drug cocktail was constitutional. An execution scheduled for Wednesday in Mississippi would be the second.

Two more men could be scheduled for execution within the next few days after the Georgia Supreme Court on Monday lifted stays in place since last October, when the U.S. Supreme Court agreed to hear a challenge to lethal injection filed by a Kentucky inmate.

After the high court affirmed the method's constitutionality, Georgia became the first state to resume executions when William Earl Lynd was put to death May 6 for the 1988 slaying of his live-in girlfriend.

Crowe tried to stop his execution by making some of the claims raised in the U.S. Supreme Court case and in Lynd's appeals earlier this month.

Crowe, a former manager trainee at Wickes in Douglasville, was having financial problems when he went to the lumber company on March 2, 1988, and struck up a conversation with the 39-year-old Pala as he was closing the store.

When Pala's back was turned, Crowe shot Pala, hit him with a paint can, poured paint over his face and struck him in the head with a crowbar. Crowe left with $1,160 in cash.

Crowe pleaded guilty to murder even though he faced a capital prosecution, but the jury deciding his punishment was not told of the guilty plea as part of mitigation to the crime, Ann Fort, one of his lawyers, has said. Fort also insisted Crowe did not plan to commit armed robbery on the night of the killing.