Ah, so you are familiar with the reasons why crime in rural areas are underreported. At least I don't have to explain it to you.
The FBI has some phrase about how the Wild West is still wild, that it was never tamed, that it is still lawless. This is why. No one around to witness, hear cries, called 911, report that it was kind of funny that the neighbor was loading up a rather heavy duffel bag into the trunk of their car, no somebody to spot someone off the highway digging a hole, how somewhere in some arroyo somewhere there was a stench of rotting bodies,,,
That, coupled with the fact that much of the West was settled by people from Southern Appalachia who themselves were known for a high propensity towards violence (gun culture, long-standing shoot-em-out fueds, constantly calling for civil war, etc).... adds up to higher than average violent crime rates extending in the Southeast westward.