Chester Morris

as Pop Weaver

as Dr. Carlo Lombardi

as Jeffrey Andrews

as Horatio 'Boston Blackie' Black

as Boston Blackie

as Boston Blackie

as Bill Brooks

as Hal Wilson

as Doctor Craig

as Robert 'Bob' Sangster

as Jimmie 'Office Boy' Burnham

as Neil Broderick

as R. Burton "Danny" Jones

as William 'Bill' / 'Willie' Legendre Jr.

as Jimmie Martin

as John Hawks

as Detective Anderson

as John Morgan

as Ted

as Chick Williams