A fire overnight at Nixon High School leaves a portable building heavily damaged. Now fire investigators are trying to determine if it was arson. Pictures sent in to our newsroom show the magnitude of the flames, that engulfed a portable building on the campus of Nixon High School last night around 2 am. "It was a portable building that was fully involved, the units got on scene, started to initiate a fire attack and they extinguished the fire.” Says Fire Chief, Steve Landin. This morning the damage was assessed. The building house 6 classrooms, three of which were completely destroyed. "Three of the classrooms of the six completely damaged the other three had heavy smoke and water damage." According to Veronica Castillon with the district. "The students are set to move in there in January for instruction, those six classes were going to be for vocational education type classes." Officials say due to the circumstances around the fire, they feel it's suspicious. "I will tell you that there was no electrical service to that facility at that time and there wasn't any utilities to that part of the building." The district says while the investigation continues, they won't let this deter their construction plans at the school. LISD Crimestoppers is offering a 200-dollar reward for information leading to the arrest of those responsible for the fire.