What is the foreshadowing in the book destructor?

In the story "The Destructors" by Graham Greene, there is foreshadowing of the gang's destructive tendencies through their disregard for authority and tradition, as well as their choice to undermine Mr. Thomas' house. Additionally, the gang's leader, Blackie, expresses a sense of unease about the consequences of their actions, hinting at the future destruction that will unfold.