Shootings In Cambridge, Watertown Draw Massive Police Response

CAMBRIDGE, MA - APRIL 19: A lone person walks past closed businesses in Harvard Square on April 19, 2013 in Cambridge, Massachusetts. After a car chase and shoot out with police, one suspect in the Boston Marathon bombing, Tamerlan Tsarnaev, 26, was shot and killed by police early morning April 19, and a manhunt is underway for his brother and second suspect, 19-year-old Dzhokhar A. Tsarnaev. The two men are suspects in the bombings at the Boston Marathon on April 15 that killed three people and wounded at least 170. (Photo by Kayana Szymczak/Getty Images)