LOS ANGELES (AP) — Prosecutors say twelve employees including a pair of librarians from four Southern California school districts have been indicted for stealing thousands of textbooks.

Los Angeles County District Attorney Jackie Lacey said in a statement Thursday that those arrested in a huge scheme set up by a book buyer include a campus supervisor, a former warehouse manager and the two librarians.

Those indicted come from financially troubled school districts in Los Angeles, Inglewood, Lynwood and Bellflower.

The indictment alleges that the employees were recruited by 43-year-old Corey Frederick, operator of Doorkeeper Textz in Long Beach, who paid school employees anywhere from $600 to $47,000 per person for stolen books, then resold them between 2008 and 2010.

Twelve of the 13 indicted pleaded not guilty. The status of the 13th was unclear.