Former Olympic canoeist David Hearn pleaded not guilty Thursday during his arraignment in federal court in Washington, D.C., for allegedly damaging the Lincoln Memorial Reflecting Pool in the nation's capital.

A grand jury has indicted him on a charge of destruction of property valued at more than $1,000 in connection to the June 19. Hearn has acknowledged putting his hand in the water amid a newly-installed liner peeling away. But he denies having ripped away a chunk. If convicted, Hearn faces up to 10 years in prison.

U.S. Attorney Jeanine Pirro said National Park Service employees witnessed Hearn "forcefully and violently" tearing up about two square feet of the liner with his "bare" hands.

Superior Court Judge Carmen McLean released Hearn on his own recognizance, and his next hearing is scheduled for Aug. 5, NBC News reported.