Gunman's Gold by Max Brand

Two miners discover a gold deposit and invite a friend, a young and very handsome gunman, to be a partner in the gold mine. An evil man overhears this invitation, commits murders, and frames the gunman for the murders, so he can claim the mine. An old friend of the young gunman's father hires a famed investigator to rescue the young man from a lynch mob. The investigator has an ugly face, but is an intelligent thinker who does not use a gun. With wits, a powerful body, daredevil deeds, and with his beautiful secretary's help, the investigator brings the guilty man to justice. His secretary learns to love a man for his inner beauty, instead of a handsome face.