Missouri's auditor plans a probe of the state agency that has come under recent scrutiny over its use of a new death penalty drug.
State Auditor Tom Schweich says the review of the Missouri Department of Corrections has already begun. The agency oversees the state prison system.
Missouri has executed two inmates in recent months after switching to a one-drug execution method using the sedative pentobarbital. A third execution is scheduled for later this month.
The state used a three-drug execution method for decade until pharmaceutical companies stopped selling those drugs to prisons. The drug comes from an Oklahoma compounding pharmacy not licensed to do business in Missouri.
The state agency says the pharmacy is part of the execution team and protected by state privacy laws.