Why is the Hastings, Michigan area so murdery, by episodes?

The Hastings area is two towns, ten miles apart, and three deaths between them over a decade. Hastings itself is a Barry County town of 7,289, and the show's history of it starts with land: 480 acres bought from a Detroit banker in 1836 and named for him. Then the sash, door and blind works, and the hardwood lumber, so the town was built on trees and windows.

Episode 233 carries two of the three, both from the mid-1980s and both tied to one double-wide mobile home outside Hastings: a June 1984 case whose body was found that July, and a second in January 1986. Two people, one household, a year and a half apart.

Episode 161 adds the third, from Nashville, ten miles out: a small man found in the countryside west of town in October 1985, a housefly tattooed on his arm, killed by a close-range shotgun blast, his money and keys still on him.