The culprit behind yesterday's bomb scare that closed down Transbay Terminal ad blocked off a four-block radius in downtown San Francisco: a bag full of dirty clothes. According to Plug 1, who shot the image above, "[i]t seems that a passenger left a gym bag on the back of a Muni bus and the driver got suspicious when he reached the end of the line with the bag still on the bus. So he called the police."