(NECN: Alysha Palumbo, Cambridge, Mass.) - A solemn tribute to a life lost but a spirit that won't be forgotten.
Six months after MIT Police Officer Sean Collier was gunned down in his squad car, allegedly ambushed by the Boston Marathon bombing suspects, a temporary memorial was unveiled -- immortalizing Collier's badge number and providing a place to grieve for his family, friends and fellow officers.
"He was a man of character, he was an individual that knew exactly where he was going and how he was going to get there," MIT Police Chief John DiFava said.
Collier had plans to join the Somerville Police Department, but never got to realize that dream.
MIT Police Chief John DiFava says it's still difficult to fathom that the morning of April 18, Collier was living his life, not knowing what lay ahead.
"Twenty-seven-years-old, at the top of his game, with a whole lifetime ahead of him, in 13 hours he's going to be gone, it's very hard," Chief DiFava said.
Questions surrounding the manhunt for the bombing suspects remain, including ones that suggest Collier's murder could have been prevented.
In fact, Iowa Senator Chuck Grassley has asked the FBI if it had Tamerlan and Dzhokhar Tsarnaev under surveillance before it released their photos to the public.
The FBI responded angrily Friday, saying "no one was surveilling the Tsarnaevs and they were not identified until after the shootout."
The agency went on to say its Joint Terrorism Task Force was at MIT April 18 "on a matter unrelated to the Tsarnaev brothers."
Instead of dwelling on what can't be changed, Chief DiFava said he wants to focus on honoring Collier's life and legacy.
Chief DiFava said, "It gets you to pause to kind of get your thoughts together and realize that we can't forget this kid, we just can't."