There is, as I mentioned a few threads ago, a very vague connection between JJ and the Rhodens, through his police partner in crime when R. Rooker was shot, TD. That, of course, requires JJ and TD to be more than work acquaintances who happened to kill a guy together. I wouldn't read too much into that, though. But I think JJ could fit the profile for a couple of scenarios, alone, or with one accomplice. Steroides makes it even more plausible, and looking at the pictures of the guy before and now confirms that imo. So I would keep him on my (long) list until someone convinces me otherwise.
I have a question. Would it be appropriate for a police officer to be facebook friends with a criminal? I noticed DR is friends with a major at the PC sheriffs office. But I guess you befriend as many as you can being a cop.
Edit: I was going towards DR not being a criminal since she had a cop friend.