Police sought a gunman who fired two shots into a crowded RTD bus as it drove through South-Central Los Angeles. The gunman fired into the front window of the bus and one shot shattered the glass, slightly injuring a passenger standing by the bus driver, Los Angeles Police Lt. Marion Helenkamp said. The second shot entered through the driver's window and lodged in his sweater, but he was uninjured. The gunman escaped the scene, Western Avenue at Jefferson Boulevard, in an unidentified car, Helenkamp said. No motive was known for the shooting, but Helenkamp said investigators believe it might have been related to an earlier incident during which the bus, going through a yellow light at Western and Martin Luther King Jr. Boulevard, cut into the path of a westbound car. The driver of the car yelled angrily and might have threatened the driver, she said.