While listening to Tampa International (KTPA) approach on 08/28, I caught one of the controllers talking to JENA 32. At one point the controller called JENA 32 several times with no response, but JENA 024 ("Zero-Two-Four") came up and advised he was working with JENA 32 "on another radio" and he would pass along the instructions. The TPA approach controller just wanted to advise the JENA aircraft not to stray any further west as they would get mixed up with departing Tampa traffic. JENA 024 also advised TPA that they were trying to get JENA 32 on a target, then JENA 024 would depart the area.
Unfortunately I was not able to find what frequency the other radio might have been on.
Reports are that the "JENA" (here it was pronounced JENN-AH) aircraft are FBI operations using non-FBI pilots. The "ROSS" FBI aircraft call sign is still being used, and is reported to indicate that an FBI pilot is in command.
UPDATE!
Searching the Internet produced this video on YouTube:
http://www.youtube.com/watch?v=kldMbyNLXpM
The poster claims this is a military contractor flight landing at DCA and was using the call sign "JENA 611". Could the JENA flights heard on surveillance operations be DoD contractor pilots working FBI aircraft???