Article Photos: Boston bombing suspect captured, brother killed 34/55

This undated photo provided by the Middlesex District Attorney's Office shows Massachusetts Institute of Technology Police Officer Sean Collier, 26, of Somerville, Mass., who was shot to death Thursday, April 18, 2013 on the school campus in Cambridge, Mass. Authorities said surveillance tape recorded late Thursday showed one of the Boston Marathon bombing suspects during a robbery of a nearby convenience store before Collier was shot to death while responding to a report of a disturbance. (AP Photo/Middlesex District Attorney's Office)