Boston Terror Attack and Lockdown: A Timeline

Boston Terror Attack and Lockdown: A Timeline

Memorials for the Victims are Created

Three crosses for each of the three people killed in the Boston Marathon bombings are seen at a makeshift memorial on Boylston Street in Boston, 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