What may have started out as a harmless prank, quickly spiraled out of control. Mary and her husband, Ron, began receiving threatening letters accusing Mary of a salacious affair she swore she knew nothing about. After weeks of harassment, a phone call was placed to Ron from the writer... and Ron recognized the voice. Minutes later, Ron was dead.

Sources:

https://www.mentalfloss.com/article/633984/circleville-letters-unsolved

https://newspaperarchive.com/circleville-herald-aug-20-1977-p-1/

https://newspaperarchive.com/dover-times-reporter-mar-04-1983-p-17/

https://newspaperarchive.com/xenia-daily-gazette-oct-24-1983-p-2/

https://www.pressreader.com/uk/chat/20170615/283686889578842

https://issuu.com/southeastohiomagazine/docs/masterwinter-spring2013_web/45

https://www.historicmysteries.com/circleville-letters-mystery/

https://www.youtube.com/watch?v=iF6yT09ERiE