Vanderbilt Football Trial: Key Witness to Take the Stand

A key witness is expected to take the stand today in the sexual assault trial of two former Vanderbilt University football players, one day after graphic video of the alleged assault was aired in court.

Jaborian McKenzie, one of the former players accused of being involved in the June 2013 incident, is slated to testify in the trial of former teammates Brandon Vandenburg and Corey Batey. Another former player, Brandon Banks, is also expected to testify for the prosecution.

Co-defendants Vandenburg and Batey sat stone-faced in a Nashville courtroom Monday. The two former teammates are both charged with five counts of aggravated rape and two counts of aggravated sexual battery. Banks and McKenzie also face charges of rape and sexual battery, but have not yet gone to trial. All have pleaded not guilty.

Detectives described the alleged attack in court Monday, providing context to video evidence. Jurors saw three videos too graphic to show to the rest of the courtroom. Vandenburg allegedly recorded the assault on his cellphone and is also being charged with one count of tampering with evidence and one count of unlawful photography.

Investigators say Vandenburg texted graphic images of the alleged attack to his friends, then searched Google to find out whether police could retrieve deleted photos. The victim, whom ABC News has declined to identify because of the nature of the alleged crime, was a neuroscience major at the university and Vandenberg's girlfriend at the time.

"Little did she know that day that had such great promise for her turned into her worst nightmare. A nightmare she relived for a long time," Deputy District Attorney Tom Thurman said.

Prosecutors claim that surveillance video shows Vandenberg carrying the alleged victim to his dorm room, with Batey by his side. According to prosecutors, the four players, who've since been kicked off the team, laughed at the victim before they allegedly assaulted her.

Defense attorney Fletcher Long says everyone made mistakes that night, even the alleged victim.

"She drank quite a lot of alcohol," Long said.

Batey's lawyer, Worrick Robinson, claims it's the college culture of sex and binge drinking that put his client in the situation.

"It was a culture that encouraged sexual promiscuity but not, not just alone, it was also a culture of alcohol, and alcohol consumption. Alcohol that changed him, changed others, and changed several people on the morning of June 23, 2013," Robinson said.

ABC News Chief Legal Affairs Anchor Dan Abrams said a lot hinges on whether the jury believes McKenzie and Banks when they take the stand.

"The defense will argue that you can't believe them because they have such an incentive to say what the prosecution wants them to say," Abrams said. "But if they come across as credible, Brandon Vandenberg is in trouble."