A media advocacy group and the American Civil Liberties Union are asking Missouri's highest court to settle whether the state's prison officials must publicly reveal their source of the execution drug pentobarbital.
The nonprofit Reporters Committee for Freedom of the Press, the ACLU and others asked the Missouri Supreme Court in a filing Wednesday to resolve the issue that's produced conflicting low court rulings.
The Missouri Department of Corrections has refused to disclose its pentobarbital supplier, saying the identity is shielded by a state law.
Opponents believe the drug could come from compounding pharmacies that do not face the same approval process or testing standards of larger pharmaceutical companies.
The filing says "any resolution of this question directly affects the ability of the public to exercise effective oversight."