The problem with these sorts of incidents is that on the unlikely chance it had been an actual terrorist attack, the police could be sued if they wasted any time at all. That would include calling the closed library.
That's the problem with this whole thing: the police can't afford to verify the calls and have to treat all of them as real.
Scenario goes like this: 911 call comes in 911 dispatcher verifies location and forwards dispatch info to local police Local police flag this up to SWAT for immediate response WHILE AND AT THE SAME TIME calling the library for verification Local police discover it's a prank and notify SWAT en-route so that when they arrive, they're expecting everything to be fine and just do a once-over with a single uniformed officer instead of a full SWAT deployment.
Nobody gets sued, nobody gets harmed, and the SWAT team is ready for redeployment much faster than otherwise (plus, they have MUCH less paperwork to fill out).
911 operator gets no answer as the library IS CLOSED DID YOU MISS THAT PART? I was a first responder who backed up the local SWAT team a few times, both real & false alarms. These guys take everything, including their training mock scenarios very seriously. I got shot (training rounds still hurt like a mother-) for showing up late at a mock hostage scenario at a local sports stadium once. The bad guys took control of the announcers booth, and were holding the PA guy hostage. It was funny hearing the bad guys demand a million dollars and a helicopter on the 50 yard line over the PA and insulting the SWAT team the whole time. I can only imagine what someone outside was thinking if they heard that.
But of course, the person who is stealing your credit card info is most likely your waiter, and they have a minute or two with your card over at the POS to copy down the CVV manually.
And this is why the United States needs to move to EMV (Chip & Pin) like the rest of the world. Rather than the waiter taking your card away, they bring you a hand-held terminal, which you then take and perform the last portion of the contract yourself, with the card never leaving your hands.
Funny, my new Chip & PIN card came in the mail from one of my CC last week...still no word on the PIN yet, perhaps I need to contact them directly & no it is not my current bank...