SIOUX FALLS, S.D. (AP) — A South Dakota prison inmate facing execution next month is objecting to the state’s choice of lethal drug to use on him.

Sixty-three-year-old Charles Russell Rhines wants the state to follow the lethal injection law that was in place when Rhines was sentenced to death in 1993.

The Argus Leader reports the state intends to use pentobarbital, commonly used to euthanize animals.

But attorneys for Rhines argue in a complaint filed Tuesday that by using pentobarbital, the state is violating Rhines’ right to choose his manner of execution and his right to due process.

The state has not filed a written response. A hearing is set for Oct. 29.

Rhines was convicted of fatally stabbing 22-year-old employee Donnivan Schaeffer while Rhines burglarized a Rapid City doughnut shop in 1992.