A lone bicycler rides across the Longfellow Bridge to Boston from Cambridge while the area is under lockdown. The manhunt continues for a suspect in the terrorist bombing of the 117th Boston Marathon earlier this week. Dzhokhar and Tamerlan Tsarnaev, suspected of the Patriot’s Day bombing, apparently hail from Russia's war-torn Chechnya but had been in the U.S. for several years. Tamerlan reportedly died in a shootout with police on April 19. His younger brother fled and is being sought by police.