A man looks out of his window in Cambridge, Massachusetts April 19, 2013. Police killed one suspect in the Boston Marathon bombing, Tamerlan Tsarneav, in a shootout and mounted house-to-house searches for the second man, his brother Dzhokar Tsarnaev, on Friday, with much of the city under virtual lockdown after a bloody night of shooting and explosions in the streets. REUTERS/Shannon Stapleton (UNITED STATES – Tags: CRIME LAW CIVIL UNREST) – RTXYSFW
Anchor Aaron Schachter talks to national security expert Sean Burke of Northeastern University about the unprecedented imposition of a lock-down on much of greater Boston.