The allegations were made in Twin Lakes, Wis., July 8. Johnson was arrested at his Genoa City, Wis., home July 13.
Johnson was placed on administrative leave with pay in Lake County pending the outcome of the criminal and internal cases against him. Johnson has been stripped of all police powers and his gun, badge, I.D. and all other sheriff's office equipment has been confiscated from him, a Lake County press release said.
According to a complaint filed by authorities in Kenosha County, Johnson allegedly showed up July 5 at a former girlfriend's office, where he physically accosted her and exposed himself.
The Associated Press contributed to this report.