They may be using an cellular PTT system, using a pure data based CAD, or have migrated to one of the SMR services as I can not find a single valid FCC lic for them anymore. As all the licenses are now expired/terminated, that would seem to be the case. They could even be on the MSWIN and not found yet, a lot of the EPA's in the south now are getting on the Statewide TRS's.... Try monitoring the SMR's and doing a TG search on MSWIN.