What are the appropriate control procedures that would have prevented or detected the theft of cash?

Tracey: Did you hear the new? Jeff: wih at news? Tracey: Bridget and Ken were both arrested this morning Jeff: What arrested? you're putting me on. Tracey: No, really. The police arrested them first thing this morning put them in handcuffs read them their rights the whole works, It was unreal! Jeff: What did they do? Tracey: Well, apparently they were filling out merchandise refund for fictitious customers and then taking the cash. Jeff: I guess I never thought about that. How did they catch them. Tracey: The store manager noticed that returns were twice that of last year and seemed to be increasing. When he confronted Bridget, she became flustered and admitted to taking the cash apparently over $150200 in just three months, They're going over the last 6 months transactions to try to determine how much Ken Stole. He apparently started stealing first. What a appropriate control procedures that would have prevented or detected the theft of cash