I decided to go back an additional year and found that cash and other checks written from the marijuana business were deposited into the above checking account during 2015. The original SAR filing does not include that information unfortunately, I guess that is one of the reason I was hired :), so there was associated activities at one time flowing through the account but now those have all stopped. Based on this additional review information. I feel that now I am obligated to continue filing?
Your obligation to
continue filing would be based on whether or not the current activity continues to meet filing criteria. Several answers above speak to this.
What you are describing here is not about continuing activity. You've uncovered earlier activity that wasn't reported (and though I can't tell from your post, possibly not considered for filing?). If after you've completed your analysis, you determine that this activity should be reported, then report it- but not as a continuing SAR. I'd be inclined to amend the original filing if the activity resides in the same time frame. But you could also call the FinCEN help line for guidance on whether or not to treat this as an amended SAR.