I have been including emails from staff (names removed etc.) substantiating the suspicious activity based on what the subject said to them in my SAR narratives and labeling the information as a corroborative statement plus stating yes on item 20. Is this the proper way to label something as a "Corroborative Statement"?

Yes, what you are doing is consistent with FinCEN expectations. Overall, the 2012 SAR revisions were intended to be less accusatory (e.g. Subject replacing Suspect). In discussions I've had with Law Enforcement, they seek to identify any potential witnesses when following up on a SAR. Expanding from Confession on the old form is supposed to make that process easier for them.Be sure to indicate how you're storing the evidence of the statement within the narrative.

Agreed, it's something the subject said that supports your suspicions; e.g. you think the customer is structuring. When he made his last deposit the customer said to the teller, "Oh wow, I didn't realize that Betty included $9,800 in this deposit! I'll tell her to make certain she doesn't get that close to $10,000 again. I don't want you to have to waste your time filling out some government form."

A significant percentage of SAR investigations begin with gratuitous customer statements... In life, generally what people do is a lot more important than what they say. In this circumstance the rule is a little different; it's a "statement against penal interest."

Thank you Patsfan and Ken!