Authorities were still investigating Wednesday what caused a fire along state Highway 116 near Cotati on Monday that destroyed three homes.
Four people from two families lost their homes in the 5-acre blaze, which began shortly after 4 p.m. as a vegetation fire along Highway 116 near Stony Point Road, Cal Fire Division Chief Eric Hoffmann said.
The fire started on the south side of the highway, then jumped to the other side and spread to homes.
There was a report that the blaze may have been sparked by a car backfiring in the area, but Hoffman said the cause had not been determined as of Wednesday.
Three homes -- one of them unoccupied -- located on two parcels were destroyed in the blaze, and the damage is estimated at $700,000, Hoffman said.
While the fire was burning, an electrical line fell, forcing firefighters to attack the blaze from a new angle by cutting through fences of neighboring homes, Hoffmann said.
The vegetation fire was contained by 5:30 p.m. and the structure fires were contained by 6 p.m., Hoffmann said.
Watchdogs are questioning an exclusive agreement between the City of Oakland and a non-profit group, tapped to lead a multi-million dollar project to redevelop the area around the Coliseum BART station.