How does the author use foreshadowing in Among the Hidden?

The author uses Luke's fears in Chapter 22 to foreshadow the tragic outcome of Jen's rally. Jen insists that there will be safety in numbers at the rally; however, Luke questions how many kids will actually show up. His decision not to go plants doubt in the reader's mind as to whether the other kids will show. In Chapter 25, the reader realizes, as Luke does, that the rally would have made the news if it had been successful. The silence on the radio is ominous.