I suspect the Feds knew whom it was almost immediately. This was a major drop of the ball. Three days later they play dumb and stumped and they release photos for civilian help. This was just a cover their ass charade which needlessly got the Cambridge cop killed. Heads need to roll, hopefully Big Fat Sis is one of them, but we know how that will go.
Why? Really, you’re asking WHY? The fedzilla has a long list of special perps they can use for special purposes ... even tracking them, allowing them to get going (or get direct help from fedzilla, as has been proven on several occasions, including the first bombing of the WTC in the nineties, or the seven/seven terrorist plot). There is an agenda afoot which requires enough ‘controlled’ terrorism to persuade the American sheeple to surrender their Constitutional rights so the globalist new world order can be instituted without US resistence to it.