The AICPA Statement on Standard for Tax Service no. 6, Knowledge of Error: Return Preparation and Administrative Proceedings states that when the CPA has a reason to believe that a taxpayer may be charged with any type of fraud or criminal violation, the client should be advised to consult with a tax attorney before speaking to the CPA in regard to the matter at hand.
The CPA should be aware of the fact that he or she could be subject to an investigation summons or grand jury subpoena as to any communication between him or herself and a client in a criminal context. Therefore, when the CPA is faced with a situation where a client has unfiled tax returns in years where they earned reportable amounts of income or where the CPA has identified intentional client errors on previously filed tax returns, the CPA should urge the client to speak with a tax attorney before proceeding with providing additional services.