A campus security guard at the University of South Alabama early on Saturday shot and killed a freshman who the university said was charging the officer outside the police station on campus. According to a statement from the university, the officer went outside after hearing banging on a window and was repeatedly charged by the student, who was naked. The officer fired only after repeated requests that the student calm down were ignored, the statement said. The student was identified as Gilbert Thomas Collar, an 18-year-old freshman. The university has asked the local district attorney to investigate what happened. Collar's mother told NBC News that she did not understand why non-lethal force could not have been used to subdue her son, who she said was 5 foot 7 inches tall and weighed 135 pounds. "He was wearing no clothes and he was obviously not in his right mind," said Bonnie Collar. "Obviously he was not armed. He was completely naked."