Photographs of slain Massachusetts Institute of Technology campus officer Sean Collier, center, are part of a makeshift memorial near the Boston Marathon finish line in Boston's Copley

 

              Photographs of slain Massachusetts Institute of Technology campus officer Sean Collier, center, are part of a makeshift memorial near the Boston Marathon finish line in Boston
Photographs of slain Massachusetts Institute of Technology campus officer Sean Collier, center, are part of a makeshift memorial near the Boston Marathon finish line in Boston's Copley Square Tuesday, May 7, 2013 in remembrance of the Boston Marathon bombings. Authorities allege that the Boston Marathon bombing suspects were responsible for Colliers death. (AP Photo/Steven Senne)