How does the author use foreshadowing in the novel, A Toast Before Dying?

As with all mysteries, the author uses elements of foreshadowing that are not necessarily apparent until the denouement with the tying up of loose ends. For the most part, this foreshadowing is not obvious and may not be recognized as such until the end of the novel. The clues are there, though, especially with the many references to living black in a white world and Thea's hidden past. Mali's first visit with Miss Adele is the most prominent example of foreshadowing but the arcane clues are obvious to only the most astute reader. Street gossip from Bertha and from others also serves as a means of using foreshadowing, especially in the subplot dealing with Senator Michaels's dealings with the other women in his life.