The Milwaukee Fire Department says that a lieutenant with the department has resigned after charges of child sex assault were filed against him.
Lieutenant Robert Olsen gave his resignation on Tuesday afternoon.
Police in Oak Creek arrested him in November. He has pleaded not guilty to charges of second degree sexual assault of a child under the age of 16.
Prosecutors say Olson sexually assaulted a 14-year-old girl multiple times.
He later sent the girl messages pleading with her not to tell anyone, for fear of going to prison.
The preliminary hearing has been waived in his case.
A bail and bond hearing has been scheduled for December 19.