How does the author use foreshadowing in The Journalist and the Murderer?

MacDonald’s appearance on the Dick Cavett show, and Malcolm’s observations of his characteristics foreshadow her realization that parts of MacDonald's character from Fatal Vision exist in the real human being. While MacDonald may not be a killer or a psychopath, he does contain elements of McGinniss’ character. McGinniss’ inability to like and identify with MacDonald is the source of the fictitious elements of his characterization.