The building was evacuated shortly after 3 p.m. and county employees had to wait outside a block away, next to the lake.
Nelson said he doesn't know any details about the bomb threat, such as whether it was phoned in.
Among those inconvenienced by the bomb threat were judges who were trying to walk from the Rene C. Davidson Courthouse at 12th and Oak streets to the administration building via an underground tunnel, as deputies wouldn't let them, or anyone else, get through.
A judge who works in the administration building complained to a deputy that her courtroom wasn't told about the bomb threat. She said the sheriff's department should have a better system of alerting all employees about bomb threats.