Kirksey McCord Nix Jr., the former Louisiana inmate who prosecutors say ordered the murders of a Mississippi Gulf Coast judge and his wife in 1987, has been rebuffed his efforts to seek a new trial.

The U.S. Supreme Court on Monday declined without comment to hear Nix’s petition for a certificate of appealability. A certificate of appealability is similar to a post-conviction petition, in which an inmate argues he has found new evidence — or a possible constitutional issue — that could persuade a court to order a new trial.

Nix’s petition had been rejected earlier by a federal judge in Mississippi and the 5th U.S. Circuit Court of Appeals in New Orleans.