The Boston Marathon bombings committed by Tamerlan and Dzhokhar Tsarnaev stunned an America that had largely dodged effective terrorist attacks since 2001. Days after the bombing, photos of the suspects were released to the public by the Federal Bureau of Investigation, and their release kicked off an unsettling and dangerous secondary chain of events as the suspects attempted to escape the city.
These events started with the ambush murder of MIT campus police officer Sean Collier. CBS News speculates that the Tsarnaev brothers targeted Collier because they intended to murder him for his weapons:
The original question is they walked up to that car and appeared they shot the officer in the head unprovoked, that it was an assassination. But why? How did that fit into their plan? The operating theory now in the investigation is they were short one gun. The older brother had a gun. They wanted to get a gun for the younger brother and the fastest and most efficient way they could think of doing it was a surprise attack on a cop, to take his weapon and go. Officer Collier had a locking holster, it’s like a three-way lock. If you don’t know how to remove the gun, you’re not going to get it out. There was apparently an attempt to yank it and they couldn’t get it and left.
Retention holsters came about because of the significant number of law enforcement officers killed in the line of duty every year with their own firearms by suspects. The most recent such incident occurred on April 5 in Jackson, Mississippi.