On April 18, 2013, three days after the Boston Marathon bombing, the life of MIT Police Officer Sean Collier was taken, both unexpectedly and too soon. A new mini-documentary called “Collier Strong” is now honoring that life, paying tribute to a man known as an everyday hero.

“Nothing is going to change what happened,” says Andrew Collier, Sean’s brother, in the opening credits. “Nothing is going to bring my brother back.”

Collier was sitting in his car on patrol when he was allegedly shot by the Boston Marathon bombing suspects. He was just 27 years old, and transported to Massachusetts General Hospital within minutes.

“Deputy Chief Jay Perault had the unfortunate job of sitting them down and letting them know they lost their son,” says David O’Connor, sergeant of the MIT Police Department, in the film. “And we had lost a brother.”

The eight-minute documentary, sponsored by NASCAR and FOX Sports, is narrated by Boston native Donnie Wahlberg. Collier’s sisters Nicole Lynch and Jennifer Lemmerman, his stepsister Jenn Rogers, and Somerville Police Officer Bob Ankenbauer are also among those interviewed in the film.

Earlier this year, Andrew Collier launched a petition asking Congress to designate a national holiday to honor America’s first responders. His plea garnered nearly 27,000 supporters, but they weren’t the only ones willing to stand behind Sean. On the 12th anniversary of 9/11, 250 cyclists pedaled 65 miles, crossing the Boston Marathon finish line in memory of the local hero.

Collier was posthumously sworn-in as a Somerville police officer the summer. His badge was retired following the ceremony, where family and local state officials met to celebrate his life. A memorial has also been erected at MIT on the corner of Main and Vassar Street, where Collier’s life was senselessly taken.

“It’s amazing to see what an impact Sean had on so many people,” says Lemmerman.

To see that impact for yourself, watch the documentary below.

(h/t Boston magazine