Is there a hacker in the house?
If the Cabal thinks the SHTF, then that's their bolt-hole. And now they're confiscating guns. Perhaps to keep locals from expressing their feelings about this.
You don't think Q has someone on the other end of the line, awaiting the call? Procedure is important.
It's not about direct evidence. It's about establishing the connections between the players. One bit of evidence can sink them all.
What makes you think that there hasn't been an investigation? Indeed, this probably dovetails with multiple investigations already in progress. Not all LEOs like to broadcast what exactly they're investigating.