Mason Alan Dinehart Sr. was an American actor, director, writer, and stage manager.

A Study in Scarlet is a 1933 American pre-Code mystery thriller film directed by Edwin L. Marin and starring Reginald Owen as Sherlock Holmes and Anna May Wong as Mrs. Pyke. The title is taken from Arthur Conan Doyle's 1887 novel of the same name, the first in the Holmes series, but the screenplay by Robert Florey was original.