Unbalanced Vision

On a normal, quiet day in the shop as I was sitting behind the computer, a stout young fellow placed a 4-pound book on the counter. It didn't take him long to pick a book from the shelves outside, for he simply walked in front of the bookshop and swiftly came in. Then, he took out a 50-pound note expecting for some change. Unfortunately there wasn't much left in our petty cash box, so he suggested for me to hold the book while he go and get some cash. Well, that was the last I saw of him since. Thinking about it, he might have been trying to get rid of the fake money for some real cash. I might be wrong though. After hearing these theft stories that happened in the shop, it's hard not to be suspicious.