Investigators have begun to consider an “operating theory” that the two alleged Boston Marathon bombers killed M.I.T. police officer Sean Collier last Thursday because they needed an extra gun, John Miller of CBS News reported.
The murder of the 26-year-old Collier has perplexed investigators as they have tried to determine the plans and motivations of Dzhokhar Tsarnaev and Tamerlan Tsarnaev.
According to Miller, investigators are exploring a theory that the Tsarnaev brothers “were short one gun, that 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.”
