'Mentally retarded' US inmate set to be executed AFP 7/15/2013 7:14:07 PM An inmate diagnosed as "mentally retarded" is due to be executed by lethal injection at a Georgia prison later Monday barring a last-minute reprieve from the US Supreme Court.Warren Hill, 52, was already serving life in prison for the murder of his girlfriend when he bludgeoned a fellow prisoner to death in 1990. He was subsequently sentenced to death.In 2000, three doctors ruled that Hill did not meet Georgia's criteria -- regarded as the toughest in the United States -- to be classified as mentally disabled.However, those three doctors have since revised their assessments and unanimously agree that Hill, who has an IQ of 70, is a person with mental retardation.Normally that would be enough to prevent authorities from executing Hill, who is scheduled to die by lethal injection at 7:00 pm (2300 GMT) local time Monday. A 2002 Supreme Court ruling barred the execution of people suffering from mental impairment.However, Hill's lawyers say they have been "procedurally barred" from raising his case in lower courts under a federal law designed to prevent prisoners from filing multiple appeals.Hill had successfully received a stay of execution in July last year after appealing on the grounds of changes to Georgia's death penalty protocol.His lawyers' only avenue of appeal now is via a last-ditch motion filed directly to the US Supreme Court last week."All experts who have evaluated Warren Hill agree: he is mentally retarded," Hill's attorney Brian Kammer said in a statement."Mr Hill's execution would therefore be a grotesque miscarriage of justice and render the Eighth Amendment a mere paper tiger."This case presents the extraordinary circumstance where an individual who is ineligible for a capital sentence is about to be executed."Mr Hill has no recourse left but to beg the court to intervene, and we trust and hope that the Supreme Court will hear his plea."