Agent Dexter (X-9)
Shara Graustark
Pidge
Baron Michael Karsten
Blackstone
Chief FBI Agent Wheeler (as Larry Blake)
FBI Agent Tommy Dawson (C-5)
Henchman Packard
Maroni
'Jolly Roger' Ticket Barker [Chs. 1, 4, 7-9]
Rosel [Chs. 2, 6-7, 12]
Thurston
Ransom [Chs. 1-6]
Scarlett) (as Bentley Hewlett)
'Trader' Delaney [Chs. 7-9, 11-12] (as Robert Kortman)
Police Officer (uncredited)
Crewman Escaping Fire (uncredited)
FBI Agent Tracy - Phoney Newsboy [Chs. 3, 5, 7, 8] (uncredited)
Henchman Sebastian [Chs. 8, 11-12] (uncredited)
Henchman (uncredited)
FBI Agent Dyer [Chs. 1, 7] (uncredited)
Henchman Marker [Chs. 1-2] (uncredited)
Freighter Crewman [Chs. 9-10] (uncredited)
Jolly Roger Ticket-Taker (uncredited)
Marine Guard [Ch. 1] / FBI Agent Crain [Chs. 6-8, 11-12] / Henchman [Chs. 11-12] (uncredited)
The Fence [Chs. 11-12] (uncredited)
Agent Jimmie Tilden [Ch. 1] (uncredited)
FBI Agent Dunn [Chs. 1, 2, 5-7, 10, 12] (uncredited)
Sheriff (uncredited)
Policeman [Chs. 1-2] / Marine Guard [Ch. 1] / Henchman [Chs. 2, 5, 10] / FBI Agent [Chs. 7-8, 11] / 'Jolly Roger' Sailor [Chs. 9, 11-12] (uncredited)
Truck Driver [Ch. 4] (uncredited)
Lawyer Carp [Chs. 2, 12] (uncredited)