Vallejo fire officials aren't sure of the exact property where the fire started, nor are have they determined the cause.
"We're determining which backyard it stared in," said Kevin Brown, Vallejo Fire Department. "Once it reached the row of Cyprus trees behind the homes, those trees lit up really quickly and, once they caught fire, it spread to several adjacent homes."
Neighbors said they complained to one homeowner about the amount of items he kept stored in the backyard.
"There was so much stuff in the yard. I was walking on Friday and said, 'There's so much stuff in your yard, that's a fire waiting to happen,'" said Sandra Deering, a neighbor. "And now look."