- Edmund MacDonald
- Anthony Waldron
- Pamela Blake
- Shirley Clinton
- Danny Morton
- Derek Lamont
- Virginia Brissac
- Cornelia Waldron
- Joseph Crehan
- Police Chief Dan Blair
- Jack Ingram
- William Shrag
- Dennis Moore
- Agent Grant Farrell
- Richard Martin
- Detective Lt. Kirby Walsh
- Byron Foulger
- Wetherby
- Jane Randolph
- Marina Lamont
- William Ching
- Jim Farrell [Chs. 1-3]
- Joe Haworth
- Donninger
- Patricia Alphin
- Ms. Buckley [Chs. 7, 9]
- Robert Barron
- Brock [Ch. 1]
- Walden Boyle
- Mr. Skinner [Ch. 10]
- Douglas Carter
- Barron [Ch. 3]
- Frank Cody
- Smith
- Cyril Delevanti
- Prof. Jackson Parker [Chs. 5-6, 9]
- Helen Deverell
- Nurse [Chs. 2-4]
- Bruce Donovan
- Waterfront Cop
- George Eldredge
- Thomas Elliott [Ch. 4]
- Jack Grogan
- Deliveryman at Elliot's [Ch. 4]
- John Hamilton
- Dr. Kittridge [Ch. 1]
- Buck Harrington
- Bus-Ticket-Taker
- Daral Hudson
- Sgt. Ed Winthrop [Chs. 2, 6-8, 10, 12-13]
- Mauritz Hugo
- Archer [Chs. 1-5. 8, 10, 12-13]
- Warren Jackson
- Rogan
- Leo Kaye
- Officer Martin
- Donald Kerr
- Turnkey [Ch. 8]
- Perc Launders
- Officer Rogan
- Jack Lorenz
- Bus Driver [Chs. 7-8]
- Casey MacGregor
- 2nd Detective
- George Magrill
- Cabbie Harper [Ch. 2]
- Don McGill
- Det. Evans
- Howard Negley
- Chief Agent Castleton [Chs. 7-10, 13]
- Eddie Parker
- Mechanic-Thug
- Franklin Parker
- Carson [Chs. 12-13]
- Keith Richards
- Mr. Rutledge [Chs. 7-10, 13]
- Beatrice Roberts
- Dr. Walker [Ch. 13]
- Jack Rockwell
- Oil Field Watchman [Ch. 3]
- Jamesson Shade
- Physician [Ch. 9]
- Harry Strang
- William Brewster [Ch. 3]
- Bob Thom
- Thug in Wetherby's Car
- Billy Vernon
- Sub Seaman [Ch. 13]
- Emmett Vogan Jr.
- Det. Brophy [Chs. 8-9]
- Alfred Wagstaff
- Dorgan
- Anthony Warde
- Martin Brandon [Ch. 10]
