COLUMBUS, Ohio (AP) -- A federal grand jury has charged 13 Ohioans with bank fraud and conspiracy to commit bank fraud.

The U.S. Attorney for Ohio's Southern District said Wednesday the indictment alleges that from September 2016 until August 2017, the defendants conspired to unlawfully negotiate checks and money orders taken from mail collection boxes in the Columbus area.

Authorities say at least four defendants were once postal service employees. 

Authorities estimate financial institutions lost at least $150,000.