In the book, The Egypt Game, why did the professor get more out of town business than local business?

In the chapter, Christmas Keys, the Professor tells the kids that, after he had been suspected of the neighborhood girl's murderer, he had fewer and fewer customers, which gave him more time to watch their game. Afterward, he began stocking his store with things from the past; things that drew customers in from out of town and made them wonder where the pieces came from.