(AP) — The Nebraska Supreme Court has rejected an appeal by a death row inmate seeking to be released from prison.

Michael Ryan was sentenced to death for the 1985 cult-related killing of James Thimm in the southeast Nebraska town of Rulo.

Ryan filed a request with Richardson County District Court for post-conviction relief in 2012, challenging how Nebraska obtained one of three drugs that would be used to execute him. Inmates typically file post-conviction relief motions after they have exhausted all other appeals.

The lower court denied Ryan’s request without holding a hearing, and Ryan appealed.

On Friday, the state’s high court upheld the rejection of Ryan’s request, saying courts can only enter relief when a prisoner shows that a denial or infringement of his constitutional rights would nullify his conviction.