WATERTOWN - APRIL 19: As Federal agents go door to door in their search for the last suspect in the Boston Marathon bombing a woman looks out her window on Belmont Street April 19, 2013 in Watertown, ... more 
WATERTOWN - APRIL 19: As Federal agents go door to door in their search for the last suspect in the Boston Marathon bombing a woman looks out her window on Belmont Street April 19, 2013 in Watertown, Massachusetts. Earlier, a Massachusetts Institute of Technology campus police officer was shot and killed late Thursday night at the school's campus in Cambridge. A short time later, police reported exchanging gunfire with alleged carjackers in Watertown, a city near Cambridge. It's not clear whether the shootings are related or whether either are related to the Boston Marathon bombing. (Photo by Darren McCollester/Getty Images) less 
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Getty Images | Photo By Darren McCollester / Getty Images
Fri, Apr 19, 2013 4:46 PM EDT