Since you included a
at the end of your post, I assume you understand at least a few of the possible scenarios.
HB's post #4 pretty much sums up the most likely outcomes. If you were a party who helped get Robert C a visa, you could be in for some legal problems if he is elsewhere, say Liberty heights, doing something other than what he should be doing.
If you are in fact a person who is unknowingly involved with Robert's entry into the US under false pretenses, you should take whatever steps you can to ensure you are not held responsible for any debts, wrong-doing, criminal acts, etc. that Robert might be involved in while "on the loose".
You might just be an observer to this occurrence, and only want to hear everyone's opinions, which is okay. However, if you happen to be a person who is actually involved, I think you will discover it is not a position you will enjoy being in.