two veteran police officers seen caught on tape in the beating of a university of maryland student after a duke basketball game in 2010 went on trial today. prince george s county officers reginald baker and james harrison are accused of assault and misconduct, but their defense lawyer said today it was the student john mckenna who was the threat. that trial is still underway and scott broom is there live in upper marlboro. scott? reporter: well, many of have us already seen this videotape repeatedly. the case is all about that videotape. in fact, the jurors got a look at it within two minutes of the lawyers started talking today. university of maryland student john mckenna slammed against a concrete wall on knox road in college park by riot police, then beat within batons. testifying in court today he doesn t remember the incident. the prosecutor today called all this an abuse of power and violence of trust, but lawyers for the police officers said mckenna was targeted und