Police say they interviewed a person of interest in South San Francisco on Sunday but made no arrests.
They're now asking for dash camera footage from drivers who were traveling on El Camino Real between Oak Grove Avenue and Bellevue Avenue Saturday afternoon between 3:30 p.m. and 4:15 p.m.
The shooting happened outside the Hillsborough Police Department. Police say an officer was in the parking lot when he was ambushed and shot by an unknown person.
The officer fired back and the gunman ran off.
A city official says that the officer is OK and that the bulletproof vest they were wearing at the time saved their life.
PREVIOUS STORY: Public asked to shelter in place during search for Hillsborough police officer shooting suspect
Investigators returned to the scene Sunday to gather evidence.
Police say the department was specifically targeted and that Hillsborough residents don't have to be concerned.
INTERACTIVE: Take a look at the ABC7 Neighborhood Safety Tracker
"Hillsborough, Burlingame is like the safest neighborhood. I would never expect anything like this to be happening in my neighborhood," said resident Gwendolyn Cannon.
The investigation has shut down the Hillsborough Town Hall on Monday.