If you're talking about the TETRA flaw that made news recently, it's unlikely to be related. The employee in the article is in the USA where TETRA is not widely used. Can't rule it out without more details but from what's written, it sounds like he had legitimate access to the information and tools through his workplace and decided to incorporate it into his hobbies. P25 is more common for encrypted voice and text over radio within US military and law enforcement agencies. It has vulnerabilities too but the reporting on those issues is a bit older so probably won't make headlines again until something new comes out.
It makes sense that he'd have the information for military-related communications if that was part of his job (though it should have been left at work). As for the FBI and state agencies, those details could have been in the plans for Defense Support of Civil Authorities (DSCA) operations. It's the sort of thing you can figure out ahead of time so you're not scrambling to put it all together when the world is on fire. If they've rehearsed those scenarios with local and federal partners in the past, any officer worth their shiny collar would identify the need for seamless communication in order to coordinate response efforts more effectively.
Why is this downvoted? Legitimately, I don't know enough about this subject matter to discern why people are disagreeing with this poster, and why the disagreement isn't being verbalized.
It's not just this discussion, they've been checking in on my profile a few times a day recently (or running a script to take out the tedious parts) and voting most of my comments down to zero or slightly negative. I think they've got about 30 accounts to work with. Kinda telling when they hit comments in removed posts along with the ones that are still available.
There's no real harm in it and I'm not willing to spin up some bots of my own to balance the scales. Mostly just interested in seeing why and how they operate so my internet points are a small price to pay.
Anyway, the radio stuff is pretty cool once you separate out the crimes and national security implications. You mentioned not knowing enough about these topics so, while I'm far from an expert on these systems, I have had some jobs and hobbies that give me a peripheral awareness of how the pieces of the article fit together. If there are any parts you'd like to know more about, I could at least point you toward some resources on the subject.