Amongst the flurry of activity surrounding the 59th Presidential Inauguration, there were reports that some different radio call signs heard being used by some federal agencies.
Although probably not related to the Inauguration activity, a reported FBI aircraft was heard using the call sign of KONA. This was seen reported on some social media postings.
And there were several reports of Customs and Border Protection (CBP) aircraft using the call sign of TROY. The aircraft using this call were reportedly the slick, dark colored Sikorsky S-76 helicopters seen around the Washington, DC area - https://www.thedrive.com/the-war-zone/33136/the-curious-case-of-customs-and-border-protections-mysterious-unmarked-s-76-helicopters
While the FBI has several call signs they have been known to use, including ROSS, JENA and others, the CBP aircraft usually answer to the OMAHA call sign, but have been known to use special, mission-related calls.
We will see what comes up in Tampa at the upcoming Super Bowl game.