Holt of the Secret Service

Stanley Blystone

Garrity [Chs. 11-15]

George Chesebro

Rankin [Chs. 11-15]

Stanley Price

Dent [Chs. 11-15]

C. Montague Shaw

Chief John W. Malloy (as Montague Shaw)

Edward Hearn

Agent Jim Layton

Jack Cheatham

Agent Frank [Chs. 3-5, 8-9, 15]