This undated photo provided by Bill Richard shows his son, Martin Richard, in Boston. Martin Richard, 8, was among the at least three people killed in the explosions at the finish line of the Boston Marathon Monday, April 15, 2013. (AP Photo/Bill Richard)
Victims of Boston bombing
The twin bombs at the Boston Marathon killed three people and wounded more than 170 on April 15, 2013. Here are some of their stories.