Why is the Pittsfield, Massachusetts area so murdery, by murders?

Pittsfield is the heart of the Berkshires, or so the city website says. It sits in the north-western corner of Massachusetts, in Berkshire County, area code 413, with a motto James translates as benign power. The Pittsfield area reaches further than the city limits: North Adams seventeen miles to the north, and Hillsdale twenty miles away, over the New York line in Columbia County. Mill towns and hill farms, forty-eight square miles of rolling hills and old cemeteries, and in Hillsdale's case a population that peaked in 1860.

The cases run from 1979 to 2011, roughly one a decade. North Adams in 1979, still a small mill town with the shoe factories, brickyards and machine shops in memory; Pittsfield in 1997 and again in 1999; Hillsdale in 2006; Pittsfield again in 2011. Episode 413 carries five of the seven on its own. Three men disappeared from a first-floor apartment, and their dismembered bodies were later dug out of a grave in Beckett. The other two episodes bring one death each, which is how a hotspot of seven ends up spread across three towns and thirty-two years.