(AP) — Authorities are searching for a man who did not return to jail from a work release facility in Council Bluffs.

The U.S. Marshal’s Office and Iowa State Patrol say 52-year-old Michael Hannum was last seen at a work release facility around 5:40 a.m. Saturday. Authorities say they discovered he was missing during an inmate count at 7 a.m. Saturday.

Hannum is believed to be driving a silver car with the Iowa license plate number SIS-613. Authorities believe he may be across the Missouri River in Omaha, Neb.