Nebraska Gov. Dave Heineman says he has ordered a criminal investigation into the state's prison sentencing scandal. 

Heineman and Attorney General Jon Bruning announced Thursday that the Nebraska State Patrol and the Lancaster County attorney's office will review the case for possible criminal activity.  

The announcement comes in response to revelations that Department of Correctional Services employees miscalculated the sentences for hundreds of inmates, who were released before they should have been. The sentences were cut short even after they were advised of two Nebraska Supreme Court rulings that spelled out the proper way to determine a prison term.  

Bruning says he doesn't believe any crimes were committed, but the investigation is intended to make sure.