Two appellate court justices on Tuesday grilled both sides in a dispute over whether the police files from a 53-year-old unsolved murder can be released under the state’s open-records law.Plaintiff John Q. Kelly is appealing Cook County Circuit Judge Anna Helen Demacopoulos’ December 2016 ruling that the village of Kenilworth is still conducting an “active and ongoing” investigation into the September 1966 murder of Valerie Percy, the daughter of a prominent businessman and future U.S. senator. She …