Answer:
That would depend on what "restrict" means to you and what legal authority you could muster to support whatever action you are contemplating. There is no federal law that allows a bank to label activity as suspicious and, as a result, automatically deny a customer access to his funds for any period of time, let alone 60 days.
You would be looking to 1) the terms of a contract and 2) a concurrent opinion from at least one judge.