LINCOLN, Neb. (AP) — A former Nebraska state senator has filed election papers seeking to reclaim his old seat.

Sen. Steve Lathrop of Omaha announced Tuesday that he has formally entered the race to represent District 12 in the Legislature. Lathrop is looking to return after a four-year hiatus. He served as a state senator from 2007 until 2015, when term limits forced him to leave office.

Lathrop is running against incumbent state Sen. Merv Riepe, who is seeking re-election. Riepe is a Republican in the officially nonpartisan race. Lathrop is a registered Democrat.

Lathrop, an attorney, played a major role in several legislative investigations during his tenure, and oversaw changes to the once-problem-plagued Beatrice State Developmental Center. He also led some of the early investigations into the Nebraska Department of Correctional Services.