SAN FRANCISCO (KCBS) – An investigation is underway into a number of suspicious car fires in San Francisco Wednesday morning.

Four cars were set on fire and three of the four were SUV’s. Investigators said they believe it happened between 3:00 and 4:30 Wednesday morning within a 10-15 block radius in the Noe Valley and Castro neighborhoods.

“We’ll be canvassing the neighborhoods, knocking on doors, looking for surveillance,” said San Francisco Fire Department Arson Unit Captain John Darmanin. “And if anyone out there has seen something, seen someone, or individuals that look like they’re out of place, we really need you to contact the fire department.”

Investigators said it is still not clear what was used to set the fires.