INVESTIGATING A MASS SHOOTING IN FOREST PARK ILLINOIS JUST OUTSIDE CHICAGO... ABOARD A COMMUTER TRAIN IN WHAT AUTHORITIES BELIEVE MAY HAVE BEEN A RANDOM ATTACK. POLICE SAY THE SUSPECT SHOT FOUR PEOPLE IN TWO SEPARATE CARS... THREE VICTIMS PRONOUNCED DEAD ON SCENE, ONE LATER DIED AT A LOCAL HOSPITAL. THE SUSPECT INITIALLY GOT AWAY BUT WAS LATER FOUND ON ANOTHER TRAIN LINE... TRACKED DOWN WITH THE HELP OF SURVEILLANCE VIDEO. POLICE NOW TRYING TO DETERMINE A MOTIVE. "THIS, YOU KNOW, OBVIOUSLY, IS SHOCKING. YOU KNOW, IT IS UNCOMMON, YOU KNOW, TO HAVE A MASS SHOOTING LIKE THIS, ESPECIALLY THIS CLOSE TO HOME// 14:56:15 SO YOU KNOW FOR PEOPLE TO FEEL UNSAFE, YOU KNOW ITS JUSTIFIED." IN A STATEMENT.. CHICAGO TRANSIT AUTHORITY CALLING THIS AN "ISOLATED INCIDENT" AND SAY THAT "THIS HEINOUS AND EGREGIOUS ACT OF VIOLENCE