A naked college freshman from the University of South Alabama was shot dead by a campus police officer early Saturday morning for acting erratically and moving towards him in a threatening manner, university officials said.

The victim, identified as 18-year-old Gilbert Thomas Collar from Wetumpka, Ala, was shot in the chest before he charged again towards the officer and collapsed dying on the spot.

A statement from the university said: "The campus police officer responded to a loud banging noise on the west side window of the police station at 1:23 a.m., Saturday. When the officer exited the station to investigate, he was confronted by a muscular, nude man who was acting erratically."

Despite several warnings from the officer who tried to the calm the situation, Collar continued to move towards the officer in a threatening manner and challenged him to a fight, the statement said.

The officer fired a single bullet at Collar with his police sidearm which struck his chest, killing him. Collar was a high school wrestler for six years at his home town in Wetumpka, Alabama and joined USA. According to Collar's mother Bonnie, he was a two-time state qualifier in wrestling. Bonnie told CNN that she does not know why her son was behaving erratically.

"He was wearing no clothes and he was obviously not in his right mind," she told CNN.

"No one said that he had attacked anybody, and obviously he was not armed. He was completely naked."

College spokesman, Keith Ayres, declined to comment whether Collar was consuming alcohol or using drugs. Authorities are expected to perform an autopsy on Collar.

The university has requested the District Attorney's Office to conduct an external investigation. The name of the campus police officer, who shot Collar, has not yet been revealed. He has been placed on paid administrative leave until internal and external investigations are done.

Tags Death