Lawyers for a condemned Alabama inmate are pointing to problems with the state's last lethal injection as they urge the state to hold off on setting his execution date.

In a filing with the Alabama Supreme Court, attorneys for inmate Robert Melson argued that the state's last execution went "horribly wrong" after the inmate coughed for the first 13 minutes of the procedure and appeared to move after a consciousness check.

Melson's lawyers say questions remain about the constitutionality of the state's lethal injection process.

Corrections Commissioner Jeff Dunn said in December that there was no evidence that the execution went awry.

Melson was convicted of killing three employees during a 1995 robbery of a Popeye's restaurant in Gadsden. The attorney general's office is seeking an execution date for Melson.