A U.S. Supreme Court justice called off the execution scheduled Friday for a man who robbed and murdered a couple in their home 14 years ago.

The order by Justice Byron White came about seven hours before Walter Bell, 34, was to be put to death.Asked to describe Bell's reaction, attorney Eden Harrington replied, "I wouldn't say `happy' is the word. Obviously, he's nervous."

Defense attorneys turned to the high court after the 5th U.S. Circuit Court of Appeals in New Orleans refused earlier Thursday to halt Bell's execution.

The Texas Court of Criminal Appeals and a federal district judge turned down a request for a reprieve earlier this week.

Ms. Harrington, a University of Texas Law School Capital Punishment Clinic attorney who is helping represent Bell, contended he should not be executed because he is mentally retarded.