Federal Agencies, more than likely FBI. The data sound would indicate ASTRO 25 OFB Encryption, which is what I hear around the Charlotte area in the same FBI frequency listing. I can not guarantee that's what it is but that would be my guess.
Although the frequency can be assigned to any Department of Justice agency, the F.B.I. has been identified as a regular user in both Charlotte and Chattanooga in the "good, old days" ... before encryption, Nextel and cellphones.
I do not know if the F.B.I. is still the current user - or whether another agency is using the frequency.
You can still hear some clear-voice comms on the frequency when an unidentified local agency uses the frequency for airborne surveillance. The aircraft observer will call out - in the clear - a "target's" location for units on the ground. Only once have I been able to hear any ground units, and on that occasion, they were operating clear-voice also while watch a subject at a Pineville location.
The PL tone, when operating clear-voice, is 167.9 Hz. The last surveillance log I have on the frequency was during last December.