MUMBAI, India -- A residential building being constructed illegally on forest land in a suburb of India's financial capital collapsed into a mound of steel and concrete, killing at least 45 people and injuring more than 50 others, authorities said Friday. The eight-story building in the Mumbai suburb of Thane caved in Thursday evening, police said. Rescue workers with sledgehammers, gasoline-powered saws and hydraulic jacks struggled Friday to break through the tower of rubble in their search for possible survivors. Six bulldozers were brought to the scene. "There may be (a) possibility people have been trapped inside right now," local police commissioner K.P. Raghuvanshi said Friday.