 Chester MorrisHoratio 'Boston Blackie' Black | Horatio 'Boston Blackie' Black |
 Janis CarterDorothy Anderson | Dorothy Anderson |
 William WrightPaul Martens | Paul Martens |
 Richard LaneInspector Farraday | Inspector Farraday |
 George E. StoneThe Runt | The Runt |
 Robert B. WilliamsMatt Healy | Matt Healy |
 Mark RobertsGeorge Daley | George Daley |
 Dorothy MaloneEileen Daley (Uncredited) | Eileen Daley (Uncredited) |
 Joseph CrehanJumbo Madigan (Uncredited) | Jumbo Madigan (Uncredited) |
 Ben TaggartTraffic Cop (Uncredited) | Traffic Cop (Uncredited) |
 Minerva UrecalMiss Wilkinson (Uncredited) | Miss Wilkinson (Uncredited) |
 Constance PurdyWoman in Daley's Office (Uncredited) | Woman in Daley's Office (Uncredited) |
| EEd AllenPoliceman (Uncredited) | Policeman (Uncredited) |
 Kenneth BrownBoy (Uncredited) | Boy (Uncredited) |
| EEarly CantrellMargaret Dean (Uncredited) | Margaret Dean (Uncredited) |
| LLew DavisExhibit Attendee (Uncredited) | Exhibit Attendee (Uncredited) |
| EEdythe ElliottMother (Uncredited) | Mother (Uncredited) |
| JJack GardnerFrank (Uncredited) | Frank (Uncredited) |
| FFred GraffReporter (Uncredited) | Reporter (Uncredited) |
| HHarrison GreeneArthur Manleder (Uncredited) | Arthur Manleder (Uncredited) |
| FFred HowardReporter (Uncredited) | Reporter (Uncredited) |
| DDick JensenPoliceman (Uncredited) | Policeman (Uncredited) |
| HHenry JordanReporter (Uncredited) | Reporter (Uncredited) |
 Edward KeanePolice Commissioner Howard (Uncredited) | Police Commissioner Howard (Uncredited) |
| TTom KingstonNews Photographer (Uncredited) | News Photographer (Uncredited) |
 Lyle LatellDetective Sergeant Matthews (Uncredited) | Detective Sergeant Matthews (Uncredited) |
 Billy LenhartBoy (Uncredited) | Boy (Uncredited) |
| AAnne LoosNewsstand Clerk (Uncredited) | Newsstand Clerk (Uncredited) |
 George MagrillPolice Guard (Uncredited) | Police Guard (Uncredited) |
| CCy MalisPoliceman (Uncredited) | Policeman (Uncredited) |
