A reader should look to the second half of chapter 20 for this answer. Judge Ford and Sandy are continuing their questioning of game players in order to find out more background information about everybody involved. During this chapter, Ford is questioning George Theodorakis about his relationship with Violet Westing. Theodorakis explains that they were sweethearts, but he didn't have the money or fame to impress Mrs. Westing. Mrs. Westing forced the relationship to end and forced a new relationship on her daughter with some politician. Violet couldn't handle the situation and killed herself. Ford begins to put the pieces together, and she believes that Sam Westing is using this game to punish Mrs. Westing. Sam Westing believes that his former wife is to blame for Violet's death more than any other person, so he is plotting against her. This realization causes Ford to surmise that Mrs. Westing is one of the current heirs.
"We must not allow ourselves to be distracted from the real issue: Which heir did Sam Westing want punished?”
“The person who hurt him most?” Sandy guessed.
“And who would that be?”
“The person who caused his daughter’s death?”
“Exactly, Mr. McSouthers. Sam Westing plotted against the person he held responsible for his daughter’s suicide, the person who forced Violet Westing to marry a man she loathed.”
“Mrs. Westing? But that’s not possible, judge. Mrs. Westing is not one of the heirs.”
“I think she is, Mr. McSouthers. The former wife of Sam Westing must be one of the heirs. Mrs. Westing is the answer, and whoever she is, she is the one we have to protect.”