Los Angeles, CA 9--24-11

Police are investigating an act of vandalism at the California campaign office of President Barack Obama.

Just days before a scheduled visit, police say that someone or some group shot BB-gun pellets through a window Thursday evening.

They also said an object was thrown through the broken window.

No staffers were in the office at the time of the shooting.

Police have not announced if they had a description of the suspect or whether the shooting was captured on surveillance video.