As we all learned from watching The Rockford Files, small towns are extremely homicidal and conspiratorial. Every week, as Ben Stein  noted back in the 1970s, ace detective Jim Rockford would venture forth from Malibu to some backwoods hamlet  where all the denizens were covering up some sinister rural plot, only to make it back to the safety of the L.A. city limits  by the episode's end, case solved.
Thus, Audacious "Validating Stereotypes Since 2005" Epigone  calculates the rate of unsolved murders by state. The top and bottom 10s, with a higher figure indicating a higher percentage of unsolved murders:
|1. District of Columbia||56.1%|
|4. New York||44.0%|
|7. Rhode Island||42.0%|
|8. New Jersey||41.8%|
|41. West Virginia||12.1%|
|42. South Carolina||10.6%|
|45. South Dakota||9.2%|
|48. North Dakota||4.5%|
An accompanying visualization is available here . (Java only)
Oh, wait, it's almost as if TV detective shows reflect the screenwriters' neuroses more than the demographic realities. Maybe there are two different kinds of stereotypes: populist (Bad) and media (Good).