Roll of Honor
Sean Allen Collier
Incident
Patrol Officer Sean Collier was shot and killed during a large-scale manhunt for suspects in the Boston Marathon bombing.
At approximately 10:30 pm, one of the subjects approached Officer Collier as he sat in his patrol car and opened fire on him without warning, striking him several times. The subjects then attempted to steal his service weapon but were thwarted by his level-three holster.
The suspects then carjacked a vehicle and led police on a pursuit while throwing explosive devices at pursuing units. The pursuit ended in Watertown, where one suspect was killed, and a Massachusetts Bay Transportation Authority Police Officer was shot and seriously wounded in a gun battle. The second suspect was captured in Watertown the following evening after another shootout.
On April 10, 2014, Police Officer Dennis Simmonds of the Boston Police Department died of a brain aneurysm that may have resulted from a head injury he sustained during the shootout with the bombers. He had been struck in the head by shrapnel from a bomb that had been detonated during the shootout.
On April 8, 2015, the brother who was arrested was convicted of murdering Officer Collier and 29 other counts related to the original bombing and was later sentenced to death.
Officer Collier had served with the Massachusetts Institute of Technology Police Department for over one year, had previously served as a seasonal officer with the Hull Police Department for three summers, and had worked as a civilian employee of the Somerville Police Department. On August 22, 2013, he was posthumously sworn in as a Somerville police officer.
Officer Collier had served with the Massachusetts Institute of Technology Police Department for over one year, had previously served as a seasonal officer with the Hull Police Department for three summers, and had worked as a civilian employee of the Somerville Police Department. On August 22, 2013, he was posthumously sworn in as a Somerville police officer.
Survivors
Survivors include his parents and five siblings.
In Our Keeping
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BO-US-MA-D1070AE7- Stewardship
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- Added to badge.nw
- April 2, 2026
- Last updated
- July 23, 2026
Honored here by 1 sentinel - 1 tribute.
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Tributes
You barely got started.
Patrol Officer Collier gave the Massachusetts Institute of Technology Police Department 1 year.
Thank you for your service to the Cambridge community. Gone but never to be forgotten.
Rest easy, Patrol Officer Collier.
— S. Vincent Anthony, U.S. Army 1985-1993
Agency
Service Record
Incident Details
Patrol Officer Sean Allen Collier is one of 17,623 officers killed feloniously — deliberately targeted and murdered in the line of duty across the full record of this memorial — 54.2% of all 32,508 officers honored here.
In MA, 199 of 469 officers were killed feloniously — deliberately targeted and murdered in the line of duty — 42.4% of this state's fallen. That is 11.8 percentage points below the national rate of 54.2%.
National Cause Distribution
How Felonious compares to all causes of officer death in the memorial record. Sean Allen Collier's cause is highlighted.
How Sean Allen Collier Compares
Offender Outcome
Shot and killed; Sentenced to death
When Felonious Deaths Occur
Monthly distribution of Felonious deaths across the full memorial record. Sean Allen Collier is highlighted in Apr.
Weapons Used Against Officers
Most common weapons in felonious officer deaths. Sean Allen Collier was killed by handgun.