We received a letter from an attorney advising us that we paid fraudulent checks. We reviewed some of the checks and noted that the maker's signature was not forged. The signature line is blank, but were made payable to the bookkeeper. The attorney stated a dollar amount, but added that their investigation is ongoing and that they don't know the actual amount.

Should we file a SAR with the amount stated by the attorney or wait for them to complete an Affidavit of forgery?

You have 29 days to make up your mind... Let the situation mature.

Actually, I should have mentioned that we are at the 30 days. We have no idea which checks are supposedly forged.

Personally, I would wait for an affidavit or other information since you cannot determine which checks are supposedly forged. Just because you received an inquiry from an outside source regarding potential fraudulent activity is not an automatic ticket for a SAR in my mind. Do your own internal research based on the "tip" and if you don't have enough to file a SAR, don't file one.

That said, if you obtain further information in the future that does give you enough evidence to file, I would file.

Don't forget, the 30 day window starts once "you" determine that the activity is suspicious. The "you" will be different for each bank as the individual or committee in charge of making that decision will differ.