How does the author use foreshadowing in The Client?

In Chapter Four, the officer has suspicions about Mark's story and suspects that Mark witnessed the suicide. When Mark slips and mentions the lawyer's nickname, the reader knows that it is only a matter of time before the cops figure out that Mark knows more than he is telling. As smart and mature as Mark is, he is too inexperienced to pull off a huge lie, such as the one that he is attempting. The slips he makes in this chapter foreshadow the coming out of the truth.