Do I include all of these last three transactions of cash deposit in the SAR?
If you consider them suspicious, include them. If you do not consider them suspicious, do not include them.
The SAR is for you to report all suspicious activity to law enforcement. If the older transactions weren't considered suspicious previously, but in light of new information they are, then include them. If not, then don't. There is no "lookback timeframe." You go back as far as the suspicious activity takes you in the account history.
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