Rather than a suspect in the murder, Colonel Isbell was instrumental in finding Laura's body and pursuing Tom's persecution. He was an aristocrat in Happy Valley and the grandson of Captain William Dula. He served as a colonel in the local militia before the Civil War and became a second lieutenant in Company A, 22nd North Carolina Regiment in April 1861. Before he returned home he attained a captain's rank, and afterwards served in the state legislature. His plantation in Caldwell County was in German Hill, where Laura Foster lived. Even though he was actually a captain, everyone continued to address him by his original rank.
Even though Laura's body was not discovered until September, Colonel Isbell continued to search, even asking others to join him. Isbell and his father-in-law found Laura's grave when Isbell's horse sniffed the ground around where she was buried.

Isbell lived in Caldwell County, and his jurisdiction as a justice of the peace did not extend to the Elkville township in Wilkes County. His interest in the murder may simply have centered around Laura's citizenship in his county and his desire to see her killer brought to justice.

Sources:
West, John Foster. The Ballad of Tom Dula: The Documented Story Behind the Murder of Laura Foster and the Trials and Execution of Tom Dula. Durham, NC: Moore Publishing, 1970.
West, John Foster. Lift Up Your Head, Tom Dooley: The True Story of the Appalachian Murder That Inspired One of America's Most Popular Ballads. Asheboro, NC: Down Home Press, 1993.

Tom Dula - Ann Melton - Pauline Foster - James Melton
Dr. George N. Carter
Laura Foster - Colonel James M. Isbell - Zebulon B. Vance

The Story - Players - The Murder - Who Done It?