How does the author use foreshadowing in Early Autumn: A Spenser Novel?

In Chapter One, Spenser talks with Patty about her relationship with Paul and about Mel's relationship with Paul. Patty says that Mel doesn't care about Paul but simply wants to hurt her. This is a foreshadowing of the fact Spenser will eventually learn that neither cares at all about Paul, and that he's merely a pawn in their game.