Empty Graves: A Weird Western (Gideon Thorn Book #8)

Gideon Thorn investigates the disappearance of Dinah Pilcher, his sometime traveling companion, fellow investigator of the occult, and Thorn's would-be biographer. Her disappearance in Arkansas, while investigating a "strange case" of grave robberies, embroils Thorn with a local outlaw clan and practitioners of an ancient religion whose rites purportedly include raising the dead to serve as slaves or instruments of vengeance in the living world they should have left behind.