[rl3]

>So based on this statement it seems like they should back off, say shit happens, lets mourn our dead and move on.

Agreed. It's not like the investigators are totally in the dark here, either.

In addition to the rest of the FBI investigation, given the terrorist/national security nature of the case, it's likely that anything the shooters did online during the past few years was pulled and analyzed—including internet history, e-mail, chat and phone conversations—rendering a pretty good picture of both their interests and associations.

If the FBI didn't do this (they can if it's a national security case), then the intelligence community certainly did.