During a Bay Area protest last night over the failure to indict the police officers who killed Michael Brown and Eric Garner, an undercover law enforcement agent who'd been marching with demonstrators pulled out his gun and aimed it at a crowd of protestors.

The officer reportedly drew his weapon after the crowd—reported by NBC News to be about 100 people—confronted him and his partner. Several witnesses tweeted first-hand accounts of the incident.

The Oakland Police Department later confirmed one the undercover officer's presence at the march but denied that he worked for their department.