IIA Exam IIA-CIA-Part2 Topic 3 Question 14 Discussion

An employee in the sales department completes a purchase requisition and forwards it to the purchaser. The purchaser places competitive bids and orders the requested items using approved purchase orders. When the employee receives the ordered items, she forwards the packing slips to the accounts payable department. The invoice for the ordered items is sent directly to the sales department, and an administrative assistant in the sales department forwards the invoices to the accounts payable department for payment. Which of the following audit steps best addresses the risk of fraud in the cash receipts process?