Williams, 43, turned himself in after learning there was a warrant for his arrest on a charge of second-degree breach of peace, police said.
The arrest came after a months-long investigation by the Connecticut State Police after the Danbury State's Attorney’s Office discovered a video that shows Williams using unnecessary force against a handcuffed suspect on July 29, 2016, police said.
The suspect, Pierre Elhayek, had been arrested on charges of violently assaulting Danbury police Officer Joseph Pooler, police said.
The incident was captured on the dash-cam of a Danbury police cruiser, state police said. It showed Williams' walk over to the suspect, who was held on the ground by other officers, and kick Elhayek in the head, state police said.
The Danbury Police Internal Affairs Division conducted a separate investigation into this matter, and Williams was found to be in violation of several department policies, police said.
A formal disciplinary hearing will be held soon, police said. Other departmental charges may be lodged now that Williams has also been arrested, police said.
Williams was released on a written promise to appear in court. His court date is set for Thursday, Feb. 9.
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