A suspected arson at an abandoned building kept London firefighters busy Monday night.Emergency workers responded to reports of a structure fire at an abandoned building at Trevithen and Weston streets, near Spike’s Volleyball, about 7 p.m.They arrived to find heavy smoke billowing from the building.Firefighters used water hoses to extinguish the flames, later determined to be from a burning vehicle inside the building.Witnesses said teenagers have been known to hang out inside the building.”It’s been abandoned for some time,” said Platoon Chief Mike Black. “I know we’ve had several fires at this location.”Three police cruisers and an ambulance were on scene.Nobody was injured..