Did two Prince George's County police officers break the law when they struck a University of Maryland student following a basketball victory in 2010? Or were the officers doing their jobs during a riot?

During opening statements of the officers' trial Monday in Upper Marlboro, a prosecutor said that Officers Reginald Baker and James Harrison engaged in unlawful behavior, but the officers' lawyers said their clients' actions were justified.

Baker and Harrison are each charged with first-degree assault, second-degree assault and misconduct in office. They are accused in the assault of John McKenna, then 21, after the Maryland men's basketball team defeated Duke on March 3, 2010.

Thousands of students took to the streets of College Park after the victory. The prosecution's first witness, then-student Nathan Cole, described the scene as a nonviolent "celebratory gathering." But the defense described the situation as a riot, or at minimum a civil disturbance.

In a video played during court, McKenna was seen half-skipping down the sidewalk and nears police officers on horses. Baker then moved in and used his shield, slamming McKenna against the wall. McKenna ended up on the ground, and police struck him multiple times with wooden batons.

Prosecutor Joe Ruddy said that Harrison and Baker abused their power and used unreasonable force. "They must be held accountable for their actions," he said.

McKenna testified Monday that once he saw mounted police, he slowed down. He said he has "a very foggy memory" of getting hit with the shield, and then remembers being in a paddy wagon.

William Brennan, a lawyer for Baker, described the officers as "foot soldiers in this episode" who were engaging in proper police conduct. He said that Baker saw someone running toward the police line and was not following orders to clear the road and get back to campus. Baker went in to arrest McKenna, and once he was on the ground the officers struck him so that they could see his hands.

"Officers' safety is 'show me your hands,' " Brennan said, adding that the strikes "were not police brutality."