The Westing Game, by Ellen Raskin, is a mystery novel aimed at children and young adults. It’s about the death of a man named Sam Westing, who then decides to split his inheritance among sixteen apparent strangers, including characters like Chris, Turtle, and Theo. They have to solve a puzzle he left behind to see who inherits the full $200 million.
In the early part of the book, Chris sees a limping person going into Westing House, but because he stutters and sometimes has trouble getting his body to do what he wants, he fails to tell his brother Theo about it.
Chris picks up the habit of looking at people’s legs in order to figure out who is limping. He notices that Crow tends to limp. Another main character that starts to limp is Theo. (He starts limping because Turtle kicked him.) Chris also thinks of Grace as limping a bit, because she has trouble with her high heels.