At least six people were killed and 32 others injured in a suicide bombing in southern Russia, Monday. Investigators believe a 30-year-old woman from the North Caucasus province of Dagestan is responsible for the attack on a bus in Volgograd. A camera on the bus driver's dashboard captured footage of the explosion, which has been shown on state television. The Muslim-dominated North Caucuses, and Dagestan in particular, have recently become home to an Islamist insurgency. Monday's attack will likely perpetuate concerns about militant threats as the nearby city of Sochi prepares for the 2014 Winter Olympics.