Boston marathon bombing suspect seized after shoot-out: Police officer shot dead and second terrorist still on run after car chase

One of the Boston bombing suspects was in custody this morning and another was on the loose after a dramatic shootout that began on the Harvard University campus and unfolded through the suburbs of the city. Explosions and machine gun fire rocked the Watertown area hours after a police officer was shot dead. The city descended into chaos hours after the FBI released images of the two suspects, pictured right, believed to have killed three and maimed hundreds more at the finish line of Monday's marathon.