How does the author use foreshadowing in The Tortilla Curtain?

In Part I, Boyle employs foreshadowing to highlight the light-skinned Mexican's sinister quality before that character proves himself a villain. Earlier in the book, the man gives América a cup of coffee saturated with sugar, this is not a healthy drink for a pregnant woman. When Delaney encounters the light-skinned man on the hiking trail, Delaney feels threatened, even though the words they exchange are pleasant. Further foreshadowing of América's attack comes in the form of the man in the Mercedes, who violates América sexually by petting her thigh. The rape of América is, thus, a grimly anticipated event.