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Boston lockdown: Authorities order residents to shelter in place during massive manhunt

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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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.