Why is the Coeur d'Alene, Idaho area so murdery, by episodes?

The Coeur d'Alene area is a two-town hotspot in Kootenai County, Idaho: Coeur d'Alene itself and Post Falls, seven miles away. Between them they hold six murders, enough for 72nd overall and second in Idaho.

The six sit in two episodes. Episode 306 accounts for two of them, both from a single day in March 2014 in Coeur d'Alene. Episode 720 accounts for the other four, spread across Post Falls from November 1995 to some point after October 1999: one killing that November, one in July 1996, one in January 1998 and one more later on. Four murders across four years in one small town is a habit.

The show keeps returning to one detail. A man came to Post Falls by way of Sacramento and Spokane and delivered about 300 copies of a morning paper. His brother joined him and took the next route over. The killings arrive years apart, and the rest of the time the county gets on with things.