In the UK banks routinely demand from their customers detailed statements about "source of funds" if the customer makes a large deposit (over $100,000). Here is an example:
Will I face this same kind of interrogation in the United States if a large amount is wired into my account?
Please note that this is not a question about making a large cash deposit (which has been discussed, for example, in Would depositing large cash amounts cause problems) but about wire transfer of a large amount.