In an unexpected move, Cook County Sheriff Michael Sheahan has decided not to run for reelection in 2006.

Sheahan’s been in office since 1990, and had made no indications that he planned to step down.

The former Chicago police officer and alderman told Democratic party officials about his decision Sunday night and Monday morning.

Cook County Commissioner Mike Quigley says many people were caught off guard.

Sheahan has not returned calls for comment, but officials close to him say he wanted to spend more time with his family.

In recent years, the sheriff has been a frequent target of controversy. Politically, he’s taken criticism over conditions and alleged abuse at the county jail, where he’s in charge. He’s also regularly butted heads with commissioners.

Cook County Democratic officials say they plan to search for a new candidate over the weekend, and then meet next Monday to discuss their options.