In the opening paragraphs of Ellen Raskin's The Westing Game, we can already get a sense that there is something suspicious in the story line. In the first few paragraphs, it's the narrator who provides clues that there is a mystery afoot, such as the suspicious fact that the delivery boy who delivered invitations to the chosen future tenants of Sam Westing's building, called Sunset Towers, was 62 years old. The other suspicious clue concerns the fact that the invitations were signed by a non-existent Barney Northrup. It's also extremely suspicious that Barney Northrup works so hard to convince Sydelle Pulaski to take the apartment.
More clues are revealed by Chapter 6 when the characters are told at the reading of Sam Westing's will that they have been selected as potential heirs to the Westing estate and the winner of the Westing game will become the actual heir. One important clue prior the start of the game is Westing's statement in his will, "I, Samuel W. Westing, hereby swear that I did not die of natural causes. My life was taken from me--by one of you!." Prior to this clue, we are also told in an obituary read by Turtle that Sam Westing "was a dedicated gamesman" and loved dressing up in costumes, especially dressing as Uncle Sam on the Fourth of July. These two clues prove to be very important later on. The first clue mentioned above is told by Attorney E. J. Plum as he reads the will, but since the reader hears the will in Westing's voice, we are also told the clue through Westing's voice. The second clue mentioned above is told by an anonymous journalist, but since Turtle is reading the article, we again hear the clue being spoken through the voice of Turtle.
By chapters 25 and 26 Turtle is sad Sandy has died and begins to piece together that Sandy, Barney Northrup, and Sam Westing were all the same person. She is able to connect Sandy with Barney because Dr. Denton Deere states he noticed that Sandy's shin was bruised, but Turtle swears that the only person she recently kicked was Barney. In Chapter 26, Turtle holds a mock trial in which she confirms from Dr. Denton Deere that the body in Sam Westing's coffin the day the will was read could have been a "wax dummy dressed in the costume of Uncle Sam." After that, referring again to the sentence in the will, "My life was taken from me--by one of you!(it)," Turtle is able to piece together that Westing's life was indeed taken by Sandy when he took on Sandy's identity, which shows that Westing was still alive when the will was read but has since died.
As we continue to examine the chapters, we spot many more clues revealed and their solutions discovered by many other characters, but Turtle discovers the most and becomes the winner of the game.