Milwaukee police are using surveillance video in an effort to identify and track down the passenger who caused a bomb scare on an M-C-T-S bus Wednesday. Authorities were called at about 7:00 P-M. The driver says a man getting off his bus said something in passing about having a bomb. There was no direct threat to the driver or passengers on the bus, but the driver followed protocol and informed the police. No one on the bus was injured.