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.