A police officer was involved in a four car pile up Tuesday night in Jackson County. The Highway Patrol reports the crash occurred on northbound I-470, just south of Strother Road, as the officer was attempting to make a traffic stop.  Investigators said Esther Leech, 18, of Blue Springs, struck the rear of another northbound car driven by Nina Arnone, 24, of Oak Grove. Arnone then struck the police car.  The Leech vehicle continued forward and hit another car driven by Ricky Parker, 58, of Blue Springs.  Parker and his passenger, Tonya Grant, 42, received minor injuries and were transported to Centerpoint Hospital.  Arnone was moderately injured and taken to St. Luke’s East Hospital, while Leech refused treatment at the scene for minor injuries.  The officer, William Crose, 42, of Lee’s Summit, was not hurt.