NEW ORLEANS - A convicted cop-killer trying to stave off execution took his case to the Fifth Circuit Court of Appeals Tuesday, with his attorneys contending that he is too mentally disabled for a death sentence.

Kevan Brumfield and Henri Broadway were both convicted of the murder of Baton Rouge Police Cpl. Betty Smothers and the wounding of Kimen Lee, while Lee was making a grocery store bank deposit in 1993. Smothers was working off-duty security at the time. A third man involved in the attack, West Paul, got a 25-year sentence in a deal with prosecutors.

Brumfield's appeal hinges on his cognitive disability. The U.S. Supreme Court ruled in 2002 that people who are "mentally retarded" cannot legally be executed. The issue was not raised in 1995, when he was convicted.

When Brumfield initially raised the mental retardation issue, U.S. District Judge James Brady ruled that it prevented Brumfield's execution. The Fifth Circut overturned Brady's ruling. The U.S. Supreme Court decided 5-4 in June to send the case back to the Fifth Circuit for reconsideration.

The court did not indicate when it would rule.