Mystery writers occasionally need a good reason for a person who is not a member of law enforcement to get involved in an investigation. This case suggests some possibilities: In an ongoing investigation in far northeastern Montana and western North Dakota, the FBI has asked farmers and ranchers to look for signs of disturbance on the ground that might indicate a recent burial. According to this AP account  published in the Missoulian, the FBI and local authorities are searching for the body of 43-year-old high school math teacher Sherry Arnold who disappeared ten days ago while on her Saturday morning run and is believed dead. Two men have been arrested and are currently jailed in Williston, North Dakota. The once-sleepy area is in the midst of an oil boom–which may well have brought with it some unexpected dangers, and tragedy.