SOMERVILLE, Mass. (MyFoxBoston.com) -- Law enforcement officials joined Sean Collier's loved ones at a special ceremony for the slain MIT officer Thursday.
Collier was posthumously sworn in as a member of the police force during a Somerville Board of Alderman meeting.
The 27-year-old was assigned badge number 310. After the ceremony, Collier's badge number was retired.
Collier's brother, Andrew, spoke on behalf of his family, saying being sworn in as a Somerville police officer would make Sean proud. He also asked all in attendance to "be Collier strong."
"It's great that they did this because a badge was been issued and has now been retired so no one will ever hold Somerville 310 again. That will forever be Sean's and it continues to put him down in the history books," Andrew told FOX 25.
Somerville Mayor Joseph Curtatone also spoke at the ceremony.
"He touched so many lives," said Mayor Curtatone of Collier. "He crossed so many paths, just look at this room, it is a small but significant testimony the impact he had on those he served with and those he served with."
MBTA officer Richard Donohue, who was friends with Collier, attended Thursday's ceremony to honor his friend's life.
"It's something he always wanted to do and it's just awesome to be here, to be a part of it and to know that he's here and he'll be forever remembered in the city of Somerville," said Donohue.
Donohue and Collier graduated from the Municipal Police Officers' Academy together in 2010. Investigators allege the two brothers accused of setting off bombs that killed three people and injured hundreds more at the finish line of the Boston Marathon also fatally shot Collier while he sat inside his cruiser on April 18. Hours later, Donohue was critically injured during a shootout with the accused bombers.
Prior to his death, Collier had been offered a job with the Somerville Police Department. His family said he was looking forward to joining the force.
In June, Gov. Deval Patrick signed a bill allowing the 27-year-old Wilmington native to be appointed to the police department. Members of his family joined Somerville officials and lawmakers at the governor's office for the ceremonial signing.