- Grace Wexler: An elderly woman invited by Sam Westing's lawyers.
- Barney Northrup: Grace Wexler's son.
- Theo Theodorakis: A teenage boy fascinated by puzzles and cryptography.
- Grace Windsor: A widow interested in fashion.
- Flora Baumbach: A middle-aged woman concerned about her weight and health.
- Judge J.J. Ford: A retired judge and resident of Sunset Towers.
- Dr. Denton Deere: A famous psychiatrist.
- Sandy McSouthers: A young woman and part-time model known for her beauty.
- Christopher "Turtle" Westing: A wheelchair-bound, mute heir to the Westing estate.
- Sydelle Pulaski: A housekeeper and friend of Flora Baumbach.
- Doug Hoo: An eccentric man interested in electronics and spying.
- Otis Amber: An employee at Sunset Towers and member of the police reserves.
- Angela Wexler: Theo Theodorakis' sister.
- Jake Wexler: Theo and Angela Theodorakis' brother.