Come Back, Charleston Blue (movie, 1972)

Sequel to Cotton comes to Harlem. Another bad influence is hitting Harlem and Gravedigger and Coffin Ed are the two cops who will stop it. Charleston Blue was a prohibition era black gangster, dead 4 decades. When he seems to have reappeared, once again slitting throats with his Blue straight edge razors, the two cops begin a complicated search for some answers.