MIT police officer Kevin O’Connor paid tribute to fellow officer Sean Collier in front of Building 32 on Friday, April 19, 2013. Collier was killed near this location the previous night by the Marathon bombing suspects.

Ho Yin Au—The Tech

MIT police officer Kevin O’Connor paid tribute to fellow officer Sean Collier in front of Building 32 on Friday, April 19, 2013. Collier was killed near this location the previous night by the Marathon bombing suspects. Ho Yin Au—The Tech