Charlie Chan
Jimmy Chan (as Sen Yung)
Dr. Cream
Steve McBirney
Henchman Grenock
Willie Fern, museum watchman
Lily Latimer
Mary Bolton
Mrs. Joe Rocke
Edwards, radio sound man
Tom Agnew (as Ted Osborn)
Carter Lane
Dr. Otto Von Brom
Inspector O'Matthews
Judge
Prosecuting Attorney
Courtroom Officer
Tour Bus Barker
Detective Pete
Sidewalk Passerby (extra)
Attorney at Trial (extra)