Chico fire investigators are working to figure out what started a fire at a building on the Esplanade. Chico firefighters were called out around 10:45 Thursday night to the 28-hundred block of the Esplanade. When they arrived on scene, they found flames shooting through the roof. The building is an old abandoned store and Chico police said code enforcement was planning to plow it down this week. Investigators are looking into reports that a homeless man has been in and out of the building in recent weeks, but there's no way to know, at this point, if he may be to blame for starting the fire. The cause of the blaze is under investigation.