Police and fire officials are trying to figure out what sparked a three-alarm fire at an unoccupied Escondido car wash early Thursday that destroyed the building. Firefighters were called around 2:55 a.m. on a report of heavy smoke and flames showing at the car wash on North Escondido Boulevard near West Mission Avenue, said Escondido Fire Division Chief Tyler Batson. Because of the intensity of the fire, the first crews called for additional resources and took a defensive position, trying to keep the fire from spreading. In all, 45 firefighters from Escondido and neighboring departments worked nearly two hours until the fire was out. After that, crews pulled apart building material, ensuring no one had been caught in the blaze. The cause of the fire is under investigation. Investigators are looking at the possibility that people living in or around the car wash might have started the fire, Batson said. “The property management had fenced it off and boarded it up in hopes of keeping it free of people,” he said. The property manager told Batson that “it was a daily challenge” to keep the property secured. Batson said the property owner was planning to sell the site and had recently showed it to prospective buyers. A formal damage estimate has not yet been compiled. “The property is basically a complete loss,” Batson said. A car dealer south of the car wash may have suffered some water damage, he said.