Officials probe cause of San Francisco fire that destroyed fleet of minibuses

San Francisco fire officials on Monday shed light on a mysterious fire that destroyed a fleet of minibuses that were intended for use during the tourist season.

Firefighters were called around 10 p.m. on Sunday to 23rd Street in the Potrero District where a dozen buses were engulfed in flames.

Fire Captain Jonathan Baxter said it took firefighters an hour to suppress the fire.

"Some of them were completely consumed. Some of them were partially consumed and some of them have minor damage to them, and they belong to a company called SF Mini Bus Rentals, who rent out that lot and was storing those buses for the upcoming tourist season," said Baxter.

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Eyewitness Kristen Stewart, who lives in a nearby encampment said, "It sounded like an explosion. I'm pretty sure, my guess is it was some kind of Molotov somebody had thrown in and exploded."

The San Francisco Police Department and the city's fire department are conducting a joint investigation into the cause of the blaze.

"Determination at this point as to what caused the fire is merely speculative on our part," said Baxter.

Some residents said people live on the minibuses, which could mean there were open flames inside the buses.

Another resident who lives at a nearby encampment described what he saw, saying, "a pyromaniac. Some people just have a thing with setting fires.