NEW ORLEANS  — Louisiana authorities are investigating a graphic video that's gone viral on the Internet and purports to show an Alabama fan sexually abusing an unconscious LSU fan after the BCS football championship game.

In one segment, a man in an Alabama jacket exposes himself and simulates a sex act on the LSU fan after the Jan. 9 game, which Alabama won.

A New Orleans assistant district attorney says the video was sent to New Orleans police. But police say they can't investigate until the victim files a complaint.

The video was apparently taken at a Krystal restaurant in New Orleans, not far from the French Quarter.

The video is no longer posted on YouTube, though versions of it are available elsewhere, including Deadspin, a sports website.

The video opens with a seemingly unconscious man in an LSU shirt slumped motionless in a chair, his head resting on a counter.

The restaurant is packed with Alabama football fans. Chants of "Roll Tide, Roll Tide" can be heard throughout the restaurant.

Alabama fans prod the LSU fan, put empty burger cartons on his head and pose for pictures next to him.

One man, wearing an Alabama baseball cap, inserts a finger into the victim's nose, and another into his ear.

Another Alabama fan pours water on the victim's head.

The victim moves a little, then the man in the Alabama cap exposes himself, climbs on top of the LSU fan's neck and simulates a sex act.

A spokesman for Krystal's corporate office in Tennessee said in a statement that the restaurant's employees intervened when they realized what was happening.

"We are appalled that this despicable incident would ever occur," the statement read. "Something like this has never before happened in our restaurants."

University of Alabama officials are aware of the video and said they will deal with any student found to be involved.

The Associated Press contributed to this article.