He was the last casualty, dying days after the others killed in the Boston Marathon bombing.

And on Friday, friends, family and residents of greater Boston came together to insist that Sean Collier, remembered as an outgoing and friendly MIT campus police officer, will not be forgotten.

Hundreds gathered beneath a giant white tent pitched several feet from the intersection where, a year ago Friday, Collier was fatally shot as he sat in his cruiser. Authorities say he was killed by the Tsarnaev brothers, who are accused of carrying out the Boston Marathon bombing.

Collier’s slaying triggered a massive late-night police chase and multi-city manhunt that eventually led to the apprehension of the Tsarnaevs. Tamarlan Tsarnaev died following a shootout with police; Dzhokhar Tsarnarev is awaiting trial.

“Sean was taken from us in a moment of extreme evil, but that instant has never defined how we remember him on this campus,” said Sara Ferry, an MIT graduate student and friend of Collier’s. “When Sean left, love rushed in.”

Speakers noted that the 26-year-old Collier was nearing his goal of becoming an officer with the nearby Somerville police department, but in the meantime had begun taking dance classes on campus — another way to better know the students he was charged with protecting.

As attendees entered the service, they were handed lapel pins that read “MIT Strong,” and signs and pictures in memory of Collier hung in each window of the campus buildings that surrounded the ceremony. Dozens of police officers from numerous law enforcement agencies sat silently as Collier was remembered. Among them was Richard Donohue, the Massachusetts Bay Transportation Authority officer who suffered life-threatening wounds during the firefight between officers and the Tsarnaevs that followed Collier’s shooting.

“One year ago, cowards set off bombs at our beloved Boston Marathon, trying to terrorize us. It was not just a momentary terror . . . but a week-long terror. . . . Such terrors can break people’s spirit,” said Sen. Elizabeth Warren (D-Mass.), who was one of half a dozen speakers at the ceremony. “But we were fearless. . . . We did not waver. In that moment, when all of the world had its eyes on us, we responded with a cry of defiance, not of fear.”

Moments later, Sen. Edward J. Markey (D-Mass.) praised the campus’s attitude of love and togetherness. Next, Cambridge Mayor David Maher declared that the intersection where Collier was killed — at Vassar and Main streets — will now be known as Sean Collier Square.

As another way to commemorate Collier, MIT announced a scholarship in his name that will be given to a local police academy recruit each year. A 20-member team — named “Team Collier Strong” — will run the marathon in Collier’s memory on Monday.

“It’s good to know,” said MIT Police Chief John DiFava, as his eyes welled with tears, “that heroes still walk God’s green earth.”

That final word had barely emerged from his lips when the crowd shot up in an ovation that lasted minutes, as a jazz ensemble began to play “Amazing Grace.”

See the full sequence of events in the aftermath of the Boston Marathon bombings.