Nearly four years after beating an unarmed protester in the face with his riot baton, a Washington police officer pleaded guilty today to assault charges that could land him up to 10 years in prison.

According to prosecutors, on Inauguration Day 2005 officer Christopher Huxoll of the D.C. Metropolitan Police Department reported to the scene of an unauthorized protest march in Adams Morgan, where there had been reports of vandalism.

Believing mistakenly that one of the protesters was hurling bottles at him and other officers, Huxoll knocked the marcher to ground, then smacked him across the face with a baton, leaving him bruised and bloody with a broken nose. In his plea, filed in D.C. Superior Court, Huxoll admitted that the victim had made no attempt to resist.

“As the resolution of this case demonstrates, where there is sufficient evidence that excessive force was used by a law enforcement officer, this office will not hesitate to prosecute,” said Jeffrey Taylor, U.S. Attorney for the District of the District of Columbia, in a press release.

CORRECTION (Dec. 22, 11:09 a.m.): Due to a reporter's error, an earlier version of this blog item incorrectly listed Nathaniel Edmunds as one of the prosecutors leading the Huxoll case. The case was prosecuted by Assistant U.S. Attorney John Cummings of the District of Columbia and Trial Attorney Edward Chung of the Justice Department's Civil Rights Division.