"Skin Walkers" is a novel by Tony Hillerman that is part of the "Leaphorn & Chee" detective series. In the book, the physical threat comes from a serial killer who is targeting members of the Navajo Nation.
The killer is known as a "skinwalker," which is a supernatural figure from Navajo mythology that is said to have the ability to transform into an animal. However, in the context of the novel, the skinwalker is portrayed as a human who is using the guise of the legend to evade detection.
The killer's attacks are brutal and seemingly random, causing fear and panic within the Navajo community. As the story progresses, the detectives assigned to the case, Joe Leaphorn and Jim Chee, must race against time to catch the killer before more lives are lost.
Overall, the physical threat in "Skin Walkers" comes from the actions of a serial killer who is preying on members of the Navajo community, causing fear and chaos.
~~~Harsha~~~