Slain MIT officer memorialized at campus service - Article Photos 5/12

Members of a police SWAT team hold rifles while standing next to an armored vehicle outside an entrance to a memorial service for fallen Massachusetts Institute of Technology police officer Sean Collier, in Cambridge, Mass., Wednesday, April 24, 2013. Collier was fatally shot on the MIT campus Thursday, April 18, 2013. Authorities allege that the Boston Marathon bombing suspects were responsible. (AP Photo/Steven Senne)