BROOKLYN - Prosecutors claim an elevator surveillance camera caught several prison guards beating an inmate at the Metropolitan Detention Center in April 2006.

Five guards must now stand trial on charges stemming from the incident. The video appears to show inmate Kenneth Howard being tripped while entering the elevator, followed by guards stomping and kicking him. Prosecutors say that Howard was stomped so hard, the imprint of one guard?s boot was left on his shoulder.

Howard was being taken to solitary confinement when the alleged incident occurred. The guards and their supervisors later wrote memos saying that Howard was fighting and resisting them, though the video doesn?t appear to show that. In fact, an ex-guard testified in Brooklyn Federal Court Monday that he lied in his memo to cover up for his co-workers.

Defense attorneys argue that the guards were acting in self-defense, and that the use of force was justified. Prosecutors claim the beating was retaliation for an earlier confrontation between Howard and one of the guards.

Two of the guards are charged with using excessive force and three others are charged as accessories. All five face charges of obstruction of justice and making false statements.