The Trial of Mary Dugan (1929)

Broadway showgirl Mary Dugan is charged with murder in the knifing death of her wealthy lover and goes on trial for her life. When her defense counsel appears to bungle his job, Mary's brother Jimmy, a newly-licensed attorney, jumps into the case to defend his sister. Jimmy's courtroom style is unconventional, but he seems to be holding his own against the prosecuting attorney--until a surprise testimony changes the course of the trial.