A man looks out of his door as a SWAT team member knocks on his neighbors door as they search for the remaining suspect in the Boston Marathon bombings in Watertown, Massachusetts April 19, 2013.
A suspect wanted for questioning in relation to the April 15 Boston Marathon bombing is seen in handout photo released through the Boston Police Department Twitter page, April 19, 2013.
Police officers take position during a search for the Boston Marathon bombing suspects in Watertown, Massachusetts April 19, 2013. Police on Friday killed one suspect in the Boston Marathon bombing during a shootout and mounted a house-to-house search fo
Images released by Federal Bureau of Investigation (FBI) shows "Suspect 2" (L-white cap) and "Suspect 1" (R-black cap) in the crowd before the blast at the Boston Marathon on April 15, 2013.