Transcript for Video Shows Vanderbilt Football Player Carrying Victim
Good evening, and you're about to hear and see exclusive new details, in the case making news as we're on the air tonight. It's a case that would horrify any parent. Authorities say it could be playing out on any Friday night, anywhere. And you'll see the surveillance tapes right here. College athletes taking a clear leader into room 213. And what happened over the next 30 minutes would change young lives, forever. This story is stunning, and we're live tweeting and will host a live chat oat the end of the hour on Facebook. But first, here's Ryan smith. Reporter: This week, a very sour note in music city, usa. A swift verdict in a high-profile trial that drove a stake right through the heart of the heartland. An explosive, headline-making case playing out in this courtroom for the past two weeks. Details of events on a summer night -- one with an alcohol-fueled sex crime on a college campus. Recorded, instead of reported, as numerous bystanders encounter an incapacitated woman but do nothing to help her. About a half dozen individuals didn't intervene. You didn't report it to the head coach? I did not. You didn't report it to any soul on Earth did you? I did not. Reporter: The combination of indifference by some and indecency by others is about to change lives on this campus forever. While Nashville is often called the capital of country music, it's earned one other moniker -- the Athens of the south, because the city is home to at least 38 colleges and universities. And just a stone's throw from those honky-tonk bars and juke joints lies Vanderbilt university, consistently ranked as one of the nation's top 20 schools. Tony Gonzalez is a reporter for "The tennessean," Nashville's paper of record. When this story came across your desk, what was your reaction? Well, I don't think we've seen a case quite like this here in Nashville, just with the level of the institution, the serious nature of these charges. From the beginning you knew that lives were probably going to be changed. Reporter: It begins on a balmy night in June, Brandon Vandenburg -- the nation's number one junior college tight end -- is drinking with the victim at a popular bar, the tin roof. She's 21, he's 20 and the prize athlete of Vanderbilt's recruiting class. He'd actually only been on campus a couple of weeks. Reporter: Brandon Vandenberg was a star? Yes, he had it all. He probably would have started the very first game day one on Vanderbilt's football team. Reporter: When did they first meet? On his recruiting visit, which I don't think they had known each other more than a couple of weeks when the event occurred. Reporter: The female -- who works for the athletic department and is a member of the Vanderbilt dance/spirit team -- meets the 6'6" all-american from palm desert, California on a recruiting trip to Vanderbilt and shows him around campus. And now that he's there, Brandon and the young neuroscience student are having nights like this one. Both had been drinking earlier with friends before meeting up. At the bar, the booze is flowing. The victim recalls a cinnamon whisky shot, a gin and tonic, and a California Long Island ice tea. People have been drinking on college campuses for decades. These are young adults. Reporter: They leave the bar together in the early morning hours and share a cab to her place. But her house key doesn't work. So the football star comes up with a plan "B." Brandon and she go to Gillette hall in her car, Brandon is driving. Reporter: And an evening of casual fun moves to new venue -- his dorm. By the next morning, a sore body and a serious hangover are the only evidence of a night of excess. She woke up, she didn't know what happened. Reporter: And that's where the story might have ended were it not for this broken door. It is an unrelated act of vandalism that occurred over the weekend. When a maintenance worker alerts campus cops about it on Monday, they go to the surveillance video looking for a culprit. What they find instead is a Vanderbilt video like no other. They were reviewing hours and hours when they found, obviously, this alarming footage. So whoever broke that door broke this case open. Reporter: In this exclusive security surveillance video -- obtained only by "20/20" -- we see Brandon and his inebriated date pulling up to the dorm. When the car pulled up outside of the dorm, and the young woman was unconscious, essentially Vandenburg asked for help to move her into the dorm. Reporter: June 23rd, 2:32 A.M. While a police cruiser sits off in the near distance, the 20-year-old football player carries the young woman out of her black Mercedes-Benz and into gilette dorm. ABC news is blurring the image to protect the victim. Brandon and his three commodore compatriots laughing and smiling. Those were all members of the football team at that time. They all knew each other, at least a little bit. Reporter: What's your interpretation of what he is doing at that point? There is no indication that there was any nefarious intent to get her to the room. There are students all over they are seeing walk into the front lobby of Gillette, nobody says boo. Reporter: For you it's not uncommon that these four young men would carry her upstairs and no one would say a thing? It didn't appear uncommon to any resident of Gillette hall. Reporter: Then at 2:35 A.M., the woman is dragged out of the elevator and dumped on the hallway floor. Cell phone pictures are taken of her as she lays on the ground. One student moves in for a close-up. She is then moved down the hall and into room 213. It looked like they were carrying a dead body. The surveillance footage shows that in the next half hour or so, the young woman ended up back in the hallway. She was moved. She was dropped. Reporter: Shortly after 3:00 A.M., the victim has been inside room 213 for nearly half an hour with four men and a fifth who claims to have been sleeping. Brandon -- now wearing red shorts -- walks out with a towel on his head and in a damning move throws it over a surveillance camera. Later, all the players involved exit the room. And in fact, some exit the floor entirely, leaving Brandon to figure out what to do next. He makes a phone call to other teammates and they run to his rescue. They were in complete cover up mode. He came to Vanderbilt university and made it about two weeks before he got into an ordeal of a lifetime. Reporter: An ordeal, the defense says, that could have been prevented. Campus cops are in the area, but they are investigating another matter. They have 1,200 cameras all over the campus with apparently no one watching on the other end. Reporter: What happened when they saw this footage? What did the authorities do next? As I understand it, an investigation began immediately on campus that involved athletic staff, it involved the deans and other campus staff, and very quickly the city police got involved. Reporter: That's where detectives Chad gish and Jason mayo of Nashville police comes in. At the time, she knew absolutely nothing. She knew she knew she had gone out with friends the night before and that's it. Typically in a case where the victim doesn't remember an alleged sexual assault, you're gonna have a really tough time getting a conviction. Reporter: Detectives know something went on in room 213, they just don't what. And they have yet to determine if Brandon Vandenburg was the victim's protector or predator. In her heart she truly believed that Brandon Vandenburg would never let anything happen to her. Reporter: When we return -- inside the interrogation room. A battle for the truth. Then -- a second video surfaces and even grizzled detectives are stunned. It was atrocious. I tried my best to describe the images. But there's no words for it. Reporter: Stay with us.
This transcript has been automatically generated and may not be 100% accurate.