Arson investigation announced after fire at San Rafael restaurant

"The fire sprinkler system had activated and there were obvious signs of forced entry." Photo: San Rafael Fire Dept.

An arson investigation is underway after a San Rafael restaurant was set on fire Tuesday night, fire officials said Friday.

Fire crews responded at about 11 p.m. to a commercial building on Bellam Boulevard, in which a restaurant is located.

Firefighters discovered that someone broke into the restaurant and spread flammable liquid before lighting it. 

Photo: San Rafael Fire Dept.

The fire triggered the sprinkler system, which put out the fire before a lot of fire damage was done, according to fire officials. 

Video surveillance captured at least one image of someone setting the fire, fire officials said.