A good place to start would be local tv and radio stations.
https://www.newson6.com/tulsa-oklahoma-news/dewar-public-schools-closed-monday-after-online-threat
And that would bring up my next question. If this was a prank of some sort would that be illegal? Though I can’t really ask that without more details about the prank.
Despite being anxious I know it will need to play itself out a bit. A prank would be a best case scenario.