Published: May 29, 2013 6:32 AM EDT
Updated: May 29, 2013 12:05 PM EDT

STARKE, Fla. (AP) - The U.S. Supreme Court denied a stay of execution Wednesday for the man convicted of raping and strangling a young girl 22 years ago near Orlando, hours before he was scheduled by die by lethal injection.
    
The petition was the final attempt to stop 56-year-old Elmer Carroll's execution at Florida State Prison in Starke. His lawyers argued he should have been considered mentally ill at the time of the murder.
    
Department of Corrections officials have set the execution time for Carroll at 6 p.m.
    
In November 1990, Carroll was indicted on a count of first-degree murder and sexual battery for the rape and murder of 10-year-old Christine McGowan.
    
The girl lived with her family next door to a halfway house for homeless men where Carroll was staying in Apopka.
    
Carroll, who had been imprisoned twice for indecent assault on a child, had told one of his housemates that the girl was "cute, sweet and liked to watch him make boats," according to witness testimony at his trial.
    
Christine's stepfather found the girl dead in her bedroom and his truck was missing. The truck was found a short time later and an officer came upon Carroll - who had blood on his sweatshirt and genitals, while traces of his semen, saliva and pubic hair were found on Christine, according to court records.
    
Carroll's lawyers employed the insanity defense at his trial, during which they and prosecutors presented conflicting testimony from psychiatrists about Carroll's mental competency. During his two decades on death row, Carroll's lawyers argued that he's too mentally ill to stand trial or be subjected to the death penalty.

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