It happened around 7:25 p.m. in the 6700 block of South Centinela Avenue.
Witnesses said someone called them after hearing glass breaking at the office. They then noticed something had been thrown through the window. It also appears someone may have fired shots with a BB gun at the building.
No one was in the office at the time.
This comes just days before Obama is scheduled to visit L.A. He'll be here next week to raise money for his 2012 campaign.
As for the incident on Thursday, police say they have no suspect description and there are no video surveillance cameras in the area.