An Uptown Brass neighborhood fire that started in a camper trailer behind a vacant commercial building in the 6300 block of 13th Avenue Wednesday evening is under investigation. Battalion chief Matthew Haerter said the fire started around 8 p.m. He said a fire that started in the camper spread to the roof of a nearby white concrete building, causing heavy damage to its first and second floors. Firefighters battled the smoldering fire for slightly more than an hour before they had it under control. Haerter said 25 firefighters from several stations throughout the city were at the scene. Haerter said there appears to have been no injuries.