A photo provided by the San Bruno Police Department shows Nasim Aghdam. Law enforcement officials have identified Aghdam as the person who opened fire with a handgun, on Tuesday at YouTube headquarters in San Bruno, Calif.

A photo provided by the San Bruno Police Department shows Nasim Aghdam. Law enforcement officials have identified Aghdam as the person who opened fire with a handgun, on Tuesday at YouTube headquarters in San Bruno, Calif.