Sean Allen Collier
Agency patch
Patrol Officer

Sean Allen Collier

Felonious
End of Watch April 18, 2013
Age 26
Tour of Duty 1 yrs 3 mo
The Vigil Panel 162 ›
Gender Male

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

Permanent identifier
BO-US-MA-D1070AE7
Stewardship
Maintained by NeuraWeb Global Inc.
Added to badge.nw
August 2, 2026
Last updated
August 2, 2026

Honored here by 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

Type Police Department
Location Cambridge, Middlesex County, MA
Platform Identity mitpd.middlesex.ma.us.gov.nw

Service Record

End of Watch April 18, 2013
Tour of Duty 1 yrs 3 mo
Age 26
Gender Male

Incident Details

Cause Felonious
Cause Detail Gunfire
Weapon Handgun

Patrol Officer Sean Allen Collier is one of 1 officers killed feloniously — deliberately targeted and murdered in the line of duty across the full record of this memorial — 0% of all 97,772 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 42.4 percentage points above the national rate of 0%.

Massachusetts Institute of Technology Police Department
1
of 1 officers
100% Felonious
MA — Statewide
199
of 469 officers
42.4% Felonious
Nationwide
1
of 97,772 officers
0% Felonious

National Cause Distribution

How Felonious compares to all causes of officer death in the memorial record. Sean Allen Collier's cause is highlighted.

Felonious
1 (0%)
Accident
1 (0%)
Illness
1 (0%)
Cardiac
1 (0%)
Undetermined
1 (0%)
Suicide
1 (0%)

How Sean Allen Collier Compares

Age at Death
26
This officer
Avg for Felonious: 39.0 years
Years of Service
1.2
This officer
Avg for Felonious: 8.4 years

When Felonious Deaths Occur

Monthly distribution of Felonious deaths across the full memorial record. Sean Allen Collier is highlighted in Apr.

Jan
1,392
Feb
1,295
Mar
1,373
Apr
1,516
May
1,504
Jun
1,442
Jul
1,587
Aug
1,517
Sep
1,491
Oct
1,371
Nov
1,447
Dec
1,624

Weapons Used Against Officers

Most common weapons in felonious officer deaths. Sean Allen Collier was killed by handgun.

Handgun
3,684
Gun
3,592
Gun; Unknown type
1,492
Shotgun
1,109
Rifle
935
Officer's handgun
909

Incident Location

Others Who Wore This Badge

0 officers from Massachusetts Institute of Technology Police Department are honored on badge.nw.