MOBILE, Ala. – A nude University of South Alabama freshman had taken LSD and assaulted others before he chased the campus police officer who fatally shot him, authorities said Tuesday, though the student wasn't armed and didn't touch the officer.

Mobile County Sheriff Sam Cochran said at a news conference that 18-year-old Gil Collar took the potent hallucinogen during a music festival Saturday before assaulting two people in vehicles and attempting to bite a woman's arm.

Authorities said Collar then went to the campus police headquarters, where he was shot by university police officer Trevis Austin. Austin is on leave while investigators review the shooting.