BOSTON, MA - APRIL 16: A young girl cries with her mother during the vigil for eight-year-old Martin Richard, from Dorchester, who was killed by an explosion near the finish line of the Boston Marathon on April 16, 2013 at Garvey Park in Boston, Massachusetts. The twin bombings resulted in the deaths of three people and hospitalized at least 128. The bombings at the 116-year-old Boston race resulted in heightened security across the nation with cancellations of many professional sporting events as authorities search for a motive to the violence. (Photo by Jared Wickerham/Getty Images)
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Chinese student killed in Boston bombing
A Chinese graduate student studying in the U.S. was among those killed during the Boston Marathon attack.
01:43 - Source: CNN
Boston bombing 18 videos
BOSTON, MA - APRIL 16: A young girl cries with her mother during the vigil for eight-year-old Martin Richard, from Dorchester, who was killed by an explosion near the finish line of the Boston Marathon on April 16, 2013 at Garvey Park in Boston, Massachusetts. The twin bombings resulted in the deaths of three people and hospitalized at least 128. The bombings at the 116-year-old Boston race resulted in heightened security across the nation with cancellations of many professional sporting events as authorities search for a motive to the violence. (Photo by Jared Wickerham/Getty Images)
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Chinese student killed in Boston bombing
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Boston bomber breaks his silence
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Police officers with their guns drawn hear the second explosion down the street. The first explosion knocked down 78-year-old runner Bill Iffrig at the finish line. He got up a few minutes later and finished the race.
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8-year-old killed in Boston bombing
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