What a tragedy.
What sickens me as well is the fact that Trump and Hilary are already using this as an opportunity to politicize this and make it all about guns. No matter where you stand on gun control, the fact of the matter is - in the US, if you want a shotgun or automatic rifle, you can get one on the black market just as easily as it is for you to buy illicit drugs.
Obviously the FBI may need to lift its game but sadly, there isn't much you can do about these nut jobs.