Ah - sorry.
OK - I'm gonna make an executive decision and say they're using IMVU, not facebook (which I think would incriminte too many people these days).
So we have an organisation using IMVU to discretely keep in touch with, control, reward and punish their assassins - (imagine IMVU meets Matrix here - that is Matrix, NOT Inception).
It's just a coincidence that both the few SS agents and the villains are using IMVU. But would 'coincidence' be enough to keep these SS agents suspicion-free with their bosses?
If we're talking modern day facebook with a few hundred million members then I guess there'd be no issue, but with something as esoteric as IMVU?