(AP) — A lawyer for death-row inmate Michael Ryan has asked the Nebraska Supreme Court to order a review of how state corrections officials got a lethal injection drug made by a Swiss company.

Nebraska and several other states were forced to buy the drug overseas when the last U.S. manufacturer quit making it in 2010 because of death-penalty opposition from customers.

Defense lawyer Rob Kortus, of the Nebraska Commission of Public Advocacy, questions the quality of sodium thiopental in a court filing. Nebraska bought its supply from a middleman.

Sodium thiopental recently has been banned for export by the European Union and is becoming increasingly difficult to get. It is made in India and China.