In Ellen Raskin's novel The Westing Game, Sam Westing is a millionaire who dies. In his will, he claims he was murdered, that one of his heirs (sixteen nieces and nephews) did it, and that if they participate in a game, they will be given clues that will reveal the identity of the murderer.
Many of the heirs had motives to kill Sam Westing. James Hoo is a restaurant owner who is bitter and believes Sam Westing stole an idea from him that made Sam prosperous and left James Hoo struggling. In a phone conversation, one of the heirs, J.J. Ford, finds out about the motive of James Hoo.
Mr. Hoo waddled in with a tray of appetizers. The judge pointed him to the serving buffet and apologized to her caller. "I'm sorry, would you repeat that name?"
"James Hoo. He claimed Westing stole his idea of the disposable paper diaper."
Berthe Erica Crow was married to Sam Westing, and when the heirs get all the clues together, the missing letters from the stanza of "America the Beautiful" spell out her name. Since they were married previously, she could have motives for killing him due to the nature of their failed relationship, and a desire to get her share of his wealth.
At one point, Sydelle Pulaski hints that the murderer may be Chris Theodorakis because, as she says: "A wheelchair, what a perfect alibi." However, no motive is given for him to be the murderer.
Grace Wexler is an unlikeable character in many ways. She is pretentious and desires the inheritance money. She makes racist comments toward the judge and treats her daughters unfairly. But just being unlikeable doesn't prove a motive for murder.
Of course, in the end, readers learn there was no murder committed.