A Los Angeles police officer Monday pleaded not guilty to assault in the arrest of a man who claims the officer beat and kicked him unconscious after he already had been stunned, subdued and lay prone on the ground. The incident was captured on a private security camera.

Officer Richard Garcia was charged with one count of assault under the color of authority for allegedly kicking Clinton Alford Jr. while he was on the ground and restrained by other officers. The Oct. 16 altercation was caught on a security camera, but the footage has not yet been released to the public, the Los Angeles Times reported.

Those who have viewed the video said it looked as though the officer kicked Alford the way a football player would kick a field goal. However, analysis of the video showed the kick landed on Alford’s shoulder, not his head. The beating left the man with several injuries.

Alford, 22, was stopped by police while riding his bike. He said he ran because the men accosting him failed to identify themselves as police officers. It is unclear how many officers were involved or whether they were uniformed or wearing plain clothes at the time.

KNBC, Los Angeles, reported after a short foot pursuit, Alford was stunned, then punched and kicked several times by officers. The kicks were allegedly so severe he lost consciousness and a tooth filling even though, he said, he was not resisting. Alford has filed a federal civil-rights lawsuit against each officer involved, KTLA, Los Angeles, reported.

Despite the alleged beating, officers initially charged the suspect with suspicion of drug possession and resisting arrest. However, prosecutors later declined to pursue the charges.

If convicted of assault, Garcia could face three years in prison. He has been placed on administrative leave while the case remains under investigation.