Sean Collier, the 27-year-old Somerville resident and MIT police officer whom police say was shot and killed by the Boston Marathon bombers, became a Somerville police officer Thursday night.
It had been Collier's dream to join the department, and he was weeks away from being sworn in when he was killed on April 18.
On Thursday, Collier was appointed posthumously to the department, and he received badge number 310. The badge number was promptly retired.
Collier had a long history with the Somerville Police Department, serving as a member of the Somerville Auxiliary Police (the youngest person to reach the rank of sergeant in that organization), interning with the department during college and later, as a civilian, serving as an assistant IT manager. He was expecting to be sworn in as a full-fledged officer with the department in June.
Members of Collier's family attended Thursday's ceremony. As with all police swearing-in ceremonies, it took place at a Somerville Board of Aldermen meeting.
Sen. Elizabeth Warren, Rep. Michael Capuano, Massachusetts Attorney General Martha Coakley, and State Reps. Denise Provost, Carl Sciortino and Timothy Toomey also attended the ceremony.
So did MBTA Transit Police Officer Richard Donohue, who was also shot while pursuing the bombing suspects and who spent two months in the hospital. He was in Collier's class at at the police academy, according to Deputy Chief Michael Cabral of the Somerville Police Department.
Cabral said Collier "did and died doing what he loved most, and that's being a police officer."
"One of the proudest moments of [an officer's] life is when they receive their badge," said Somerville Police Chief Thomas Pasquarello. "The badge 310 will live with the Somerville Police Department eternally."
Collier's brother, Andrew, said, "This would make Sean so proud to be appointed as a Somerville police officer."
He said in the four months since his brother's death the family has met many wonderful people.
"This is quite the honor for Sean," Andrew Collier said.
He added later, "Everyone, remember to be strong. Be Collier strong. Do it for MIT officer one-seven-nine and Somerville officer three-ten."