MADISON, Wis. (AP) – An assistant Milwaukee County district attorney has been named to head the Wisconsin Judicial Commission, which investigates and prosecutes claims of misconduct against the state’s judges and Supreme Court justices.  The commission announced Thursday that it had selected Jeremiah Van Hecke as its executive director. He will take over for retiring director James Alexander on August 28th. Alexander has been executive director since 1990.  Van Hecke is a 1999 graduate of Tulane Law School.        The Judicial Commission has nine members and has jurisdiction over Wisconsin’s 500 judges, including those on the Supreme Court and appeals court, circuit and municipal courts and former judges who serve temporarily.   Five commission members are appointed by the governor and four are appointed by the Supreme Court.