OKLAHOMA CITY — A nonprofit public watchdog is suing Oklahoma Attorney General Mike Hunter for refusing to release a special audit into criminal allegations connected to the state’s effort to clean up heavily polluted communities in northwest Oklahoma.

Washington, D.C.-based Campaign for Accountability filed the lawsuit in Oklahoma County District Court Monday against Hunter and Auditor and Inspector Gary Jones, seeking the audit’s release.

Jones’ office conducted the audit in 2011 at the request of former Attorney General Scott Pruitt, President Donald Trump’s pick to head the U.S. Environmental Protection Agency. But after the audit’s completion, Pruitt ordered it not to be released.

The audit looked into suspected unlawful contracting practices of a state trust involved in a buyout of residents in the lead-polluted communities.

Hunter’s office declined comment Monday on the lawsuit.