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 report s 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.