You have to consider the nature of the legal process to decide if you need to review the account for potential suspicious activity - otherwise you're just chasing wild geese each time you get anything.
For example - if you receive a levy that is executing a judgement from a civil case, or a garnishment for civil matters. your money laundering risk is small and most likely a review of the account is not going to reveal anything. Examples of this would be civil cases for breach of contract, liability for injury, divorce, etc. Likewise, a levy for child support is not a trigger for money laundering issues.
If you want to be conservative, you can do a review of the last 12 months of activity to see if anything unusual stands out (like lots of cash or wires or unauthorized ACH returns) but digging through each and every transaction is most likely going to be a waste of resources.
However, if you receive a criminal subpoena, or a Grand Jury subpoena, or an IRS investigation, then you will want to take a closer look to see if the customer has been layering transactions, or doing an unusual movement of funds to avoid detection, etc. You will want to look at cash, wires, ACH (especially returns), and counter-parties to significant transactions (either in terms of dollar amount or number of transactions).
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CRCM,CAMS
Regulations are a poor substitute for ethics.
Just sayin'