WASHINGTON (AP) —— Florida death row inmate Clarence Hill won a last-minute Supreme Court stay Tuesday night about an hour after he was scheduled to be executed for killing a police officer.

It was not clear if the court's intervention would only briefly delay Hill's execution, which had been scheduled for 6 p.m. EST, to give justices additional time to review three separate stay requests.

Witnesses had gathered at the Florida State Prison for the execution, which was put off for more than an hour before word came from the court.

The witnesses were sent home after Justice Anthony M. Kennedy filed paperwork that said Hill's death sentence would "be stayed pending further order" of the justices.

"The court will not rule until tomorrow," said Robby Cunningham, spokesman for the Florida Department of Corrections.

Earlier, Hill had lost appeals at the 11th U.S. Circuit Court of Appeals in Atlanta. He was scheduled to die for the October 19, 1982, slaying of a Pensacola police officer and the wounding of his partner.

Hill was to be the 61st inmate executed in Florida since 1976, when executions resumed after a 12-year moratorium, and the 257th since 1924, when the state took that duty from individual counties.

Hill first asked the court for a stay last week. In one of his appeals, Hill asked for a delay to give him time to contest the chemicals that will be used. Kennedy cited that case in granting the stay.

Hill's lawyers argue that the three chemicals used in Florida's lethal injection method of execution cause pain, making his execution cruel and unusual punishment. He also contends that he is mentally retarded