Within the BSA Department, we have a person assigned to write and file SARs. We also have BSA Analysts that review various daily and monthly reports, such as cash, kiting, wires, etc. Let's say one of the BSA Analysts picks up on cash activity that appears out of the norm and questions the branch and still doesn't feel comfortable with the explanation. She then forwards that case to the SAR person to create and file a SAR. Does the detection date start from when that BSA Analyst became aware of the activity or when she notified the SAR writer, which can be a couple of days after the fact. Thank you.

The countdown starts from when the activity was determined to be suspicious.
With that said, the period of determination has to be reasonable. In the case you describe, the 30 days would be from when the analyst completed the review and determined it was suspicious.

I agree with MagicCity on the start date.