The siblings of MIT Police Officer Sean A. Collier, 27, who was killed April 18, describe their brother on the TODAY Show.
Vice President Biden spoke at the memorial for slain MIT police officer Sean Collier and condemned terrorism, saying, "Boston, you sent a powerful message to the world."
Thousands of mourners attended a memorial service for Sean Collier, the MIT police officer who authorities say was gunned down by the Boston marathon bombing suspects. His stepbrother Rob Rogers told the crowd, "People have asked me, if Sean were here, what would he think? Are you kidding me? He would love this. You've got sirens. Flashing lights. Formations. People saluting. Bagpipes. Taps. The American flag. He would have loved it. He was born to be a police officer, and he lived out his dreams."
Officer Sean A. Collier, 27, of the MIT Police was killed April 18 in Cambridge.
Dominick Reuter / Reuters
Heightened security, empty streets, and memorials mark the the day after the Boston Marathon bombings.