(AP) – Attorneys for condemned inmate Herbert Smulls are pressing on with concerns about Missouri’s execution drug, even as the state prepares for its third execution since November.

Smulls is scheduled to die by injection one minute after midnight Wednesday for killing St. Louis County jeweler Stephen Honickman in 1991. On Sunday, attorneys for Smulls filed a motion with U.S. District Court. It alleges that the state’s refusal to name the compounding pharmacy that makes Missouri’s execution drug prohibits them from proving that the execution method could cause pain and suffering for the inmate.

His attorneys have also asked for clemency from Gov. Jay Nixon.

St. Louis County prosecutor Bob McCulloch says Smulls callously planned the killing, and deserves to be executed for the crime.