EL DORADO ? Butler County Sheriff Stan Cox resigned Monday because has been called to active duty as a member of the U.S. Army Reserve.

Cox, former mayor of Leon, told Sheriff’s Department employees of his decision Friday, and on Monday the County Commission received his letter of resignation.

Cox has been sheriff since January 1999. Until his successor has been named, Undersheriff Craig Murphy will run the department, and County Clerk Ron Roberts will handle the department’s finances.

The Butler County Republican Party will choose the new sheriff. Party chairman Scott Stoskopf said a decision would be made within 45 days.