A few years ago I was working at a videogame store. We learned to recognize customers who would consistently come in with mint condition new release games and insist on trading them in for cash, despite the fact that we paid pennies on the dollar. We strongly suspected they were stealing from somewhere, but due to a lack of tangible evidence and corporate policy on the matter there wasn't much we could do about it. We started keeping a handwritten binder with details in case anyone ever asked.
One day a uniformed police officer walked into the store and straight to the cash wrap. He handed me a photo of a woman from a security camera.
Officer: "Do you recognize this woman?"
Me: "Yes, sir. She comes in here all the time and trades in new-looking games for cash."
O: "I also have this list of names..."
M: "Well, [x] is the woman in the picture. I also recognize this name, that name, and these 2 names here. I've never seen any of them come in together, though."
O: "They have been operating a crime ring where they steal from retail stores, exchange the merchandise with each other, then a different person pawns it for cash somewhere else. Do you haveany information on them?"
M: "Actually, we have this binder..."
The officer returned some time later when my manager was in the store. They went into the back and spent a good bit of time comparing transaction notes to security footage and the officer walked away with a binder full of notes, a disc full of security footage, and a huge smile. I can't imagine this ended well for the people on the list.