Boston Terror Attack and Lockdown: A Timeline

Boston Terror Attack and Lockdown: A Timeline

Night Vigil in Boston

Women hold candles as they listen to a speaker during a candlelight vigil for the victims of the Boston Marathon bombings, in Somerville, Massachusetts, April 18, 2013. Investigators released pictures of two suspects in the Boston Marathon bombing on Thursday, seeking the public's help in identifying two backpack-toting men photographed on the crowded sidewalk on Monday before bombs exploded near the finish line.

REUTERS/Jessica Rinaldi