The Georgia Supreme Court cleared the way for the execution of a convicted rapist and killer Thursday, a day after ordering a stay to review the case.

Robert Karl Hicks, 47, was to be killed by injection Thursday afternoon. He raped and fatally stabbed 28-year-old Toni Strickland Rivers in 1985.

Hicks was originally to be executed Wednesday, but the state high court ordered a stay without explanation.

On Thursday, the court decided 5-2 to deny an appeal by Hicks and allow the execution to proceed. The majority wrote no opinion.

But Chief Justice Norman Fletcher, one of the dissenters, wrote that Hicks is likely mentally retarded, and the U.S. Supreme Court recently ruled that the retarded may not be executed.

Hicks makes "a substantial and credible claim of mental retardation," Fletcher wrote, noting that Hicks has a family history of retardation, failed three grades in elementary school and suffered a head injury in a motorcycle accident.

Hicks stabbed Rivers eight times with a pocket knife, slit her throat and left her body _ nude from the waist down _ in a field near Griffin, about 35 miles south of Atlanta. Hicks, who did not know the woman, had followed her from a rural grocery where she was using a pay phone, prosecutors said.

The execution would be the first in Georgia this year and 35th since the U.S. Supreme Court reinstated the death penalty in 1976.