On April 18, 2013 M.I.T. Police Officer Sean A. Collier was killed in the line of duty while patrolling the M.I.T. campus in Cambridge, Massachusetts by accused Boston Marathon Bombers. Officer Collier was a former Special Police Officer for the Town of Lincoln from February 2011 to February 2013.

Sean was a well-respected police officer who was known for his caring and compassionate demeanor. Sean volunteered his time to various groups and organizations in order to make the community around him a better place. In honor of Sean, the Lincoln Police Association has created a permanent memorial in the lobby of the Public Safety Building.