I have read some of the past threads on tax evasion and it seems that people are spilt on filing for this purpose. My question is that if you are filing for possible tax evasion can you include information from the tax return? Example(Gross receipts or sales)

Well, I doubt if a SAR is of any value to law enforcement if you don't tell them why you believe tax evasion is involved.

There are very few things that banks are prohibited from disclosing in a SAR. Those that come to mind are National Security Letters and Grand Jury subpoenas. Beyond that, there is no "customer - banker privilege" analogous to the attorney - client privilege that would require you to withhold what could be the most damning information of all.

Moreover, if your SAR reflects suspicion of income tax evasion, any information you have that was derived from income tax returns would already be in the possession of your most interested readership, the IRS. What you have that they would be most interested in is information that indicates that income tax filings were incorrect.

Everything else is just context.

I'll third this one: you can and should. It might be the entire basis of your case.

On an unrelated note, my only suggestion, if your going strictly off a numbers game (e.g. ABC Corp deposited $XX in 2011 but reported $YY on their return) check out the IRS Bank Deposits method and try to perform as many investigative steps as you can yourself on the customer.

http://www.irs.gov/irm/part9/irm_09-005-009-cont01.html

Sometimes things that appear to be income may actually be classified in some other fashion. If there's any cash involved, specifically ask them where they got it and document their explanation in the narrative.

Great training resource!

It worked against Al Capone in 1931 and it still works today. What banks have that the IRS would need in this scenario is the dollar amount for "total deposits" during a tax year. However, you are not obligated to make their case in your SAR narrative. Your job is to suggest that if they did some digging they would find something.