Why is the Grants Pass, Oregon area so murdery, by episodes?

The Grants Pass area is five towns across the far south-west corner of Oregon, all within 24 miles of Grants Pass itself. The centre is also the biggest of them, at 38,902, and the motto is 'live rogue', after the nearby Rogue River. There's a local saying, 'it's the climate', and it answers most questions about the place. Wimer sits 13 miles out in Jackson County. Wolf Creek, 18 miles off in the hills, had about 1,695 people, and Kerby, 23 miles down, a few hundred. Cave Junction, 24 miles, is close to the California line. Stagecoach stops and gold claims turn up in all five histories.

The cases run from 1978 to 2013, with murders in 1987, 1988, 2001, 2009, 2012 and 2013. Episode 670 carries four of the eleven, in two cases from November 1988. The other four episodes add seven between them, at most two in any one.