The NTSB will release preliminary findings shortly after an aircraft accident but usually takes at least a year for the full report. No one gets all nutty about it...
Personally in a major incident like this I can see it easily taking a year or more to investigate and assemble a full, comprehensive, accurate as possible, report. Look how long it took (several days) to sort out the major details of the killings in the first place. When you consider the sheer number of witnesses, families, etc to interview, lab work to do, debriefings and interviews with responders, scene examinations, and so on...it is an astounding amount of work.
I'd rather them take the time to do it right and quietly release it than to do a quick and shoddy job for political purposes...
Some of the parents of kids killed at Sandy Hook last year want to turn the discussion into less divisive directions. Problem is, they persist in calling the problem "gun" violence, rather than "violence."
Oh, I'd say they get it. They have realized outright attacks on gun rights don't work as well as chipping away from the side. They very much do so get it...