A "person of interest" was reported to be in custody Friday, as police and firefighters searched the sprawling campus of Santa Monica College for other possible victims or shooters. By early evening, authorities declared the campus clear.
The gunman has not been identified by authorities, Santa Monica Police Chief Jacqueline Seabrooks told reporters, according to CNN.
She described him as a white male, between 25 and 35 years old, clad in black and wearing what appeared to be a ballistic vest.
Authorities believe the shootings began with a house fire and gunshots shortly before noon in a residential neighbourhood near the college. The gunman also carjacked a woman.
Inside the house, firefighters found the bodies of at least two people, Seabrooks said. Investigators believe the gunman knew the dead people in the house, but police were unsure of the connection.
The others killed in the rampage were targeted randomly, Seabrooks said.
Within minutes of the carjacking, authorities said, the gunman targeted a bus in Santa Monica, and exchanged gunfire at least once on the campus with police, Seabrooks said.
As he fled toward the campus library, he shot a woman, she said.
A number of students were in the library building studying for their final examinations when the gunman burst in. More than 30,000 students are enrolled in the two-year community college.
President Barack Obama was in Santa Monica for a fundraiser, just a 10-minute drive from the campus, according to CNN affiliate KCAL/KCBS.
Obama's schedule was not affected by the shootings or police followup.