The Riddle of the Purple Emperor

Hamilton Cleek, the Man of Forty Faces, and once known to the police as "The Vanishing Cracksman."
Superintendent Narkom, of Scotland Yard.
Lennard, his chauffeur.
Hammond } Detective Sergeants.
Petrie }
Constable Roberts, Police Officer at Hampton Village.
Dollops, Cleek's trusted friend and protégé.