Police are investigating the cause of a car accident that killed three Alabama high school cheerleaders and injured four in Friday night, November 30.Sarah Casey, 16, Courtney Niceley, 17, and Whitney Bradford, 16, of Warrior, Ala., all died when the car they were in hit a tree and went over an embankment. The driver, Sarah Elizabeth Agee, 17, Brittany Lovejoy, 17, Ariel Nibblet, 17, and...