You obviously do not have any domain knowledge about financial regulations nor the banking business at large. Accounting isn't rocket surgery, this level of activity is easy to spot, especially with software.(0) Plus requirements for tracking and reporting large cash deposits of this sort have been on the law books for years. (Not to mention the newer anti-terrorism requirements.)

(0) I've been working in the software side of the financial analysis for over a decade. While not trivial, transaction analysis is very common for various purposes including compliance.