He knows we file SARs on him and his associates
ummm ...
howdoes he know?
... anywho ...
I would do a search on the internet about this outside business ... do you 314(b) share? Does the bank he writes checks to share? Might be able to uncover the money laundering scheme. (or justify everything as legitimate)
All BSA Policies must have a section on when your bank will close an account. The examiners have been very interested in if you follow that policy or not (or at least mine have).
My banks have a type of analysis matrix - if the customer is profitable, we usually keep them. If not, we toss 'em.
If we think they are involved in something really bad (not just plain structuring - but something we could take a loss on) - we close them no matter what.