Jessica Rinaldi / Reuters
SWAT teams search for the remaining Boston Marathon bombing suspect in Watertown, Mass., on April 19.
CJ Gunther / EPA
A resident watches as police search an apartment complex in Watertown, Mass., on April 19.
NBC News reports: Boston and its surburbs, universities and transit system were on total lockdown Friday as police hunted for marathon bombing suspect Dzhokhar Tsarnaev -- on the loose after his terrorist brother was killed in a stunning chain of events that left one cop dead and another injured, officials said. Read full story
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- Anatomy of a bombing: Photos show battery, wires used in device
A tense night of police activity just days after the Boston Marathon bombings caused police to converge on a neighborhood outside Boston, where residents heard gunfire and explosions.
Charles Krupa / AP
A woman looks out a window at her home as police start to search an apartment building in Watertown on April 19.