In "To Kill a Mockingbird", Jem tells Scout something strange about getting his trousers back. What is this?

When Jem, Scout and Dill ran away from the Radley place (after Nathan started shooting), they needed to crawl under a fence, and Jem's pants got caught and torn. He undressed and left them there rather than get caught and get in trouble.

Being either brave or foolish, he goes back later that evening, when he and Scout are supposed to be asleep and Atticus is asleep. Jem is frightened because when he goes back to get his pants, they are neatly folded over the fence for him--as if someone knew he would come back for them. Upon further inspection, he finds that they have also been sewn, but not by someone with professional experience. He describes the stitches as looking crazy, like a child did them.