I may have found what you want in my research.
John COX, who lived in the Mt. Joy area west of Mt. Pleasant, Maury Co., TN
In early spring 1862 Gen Buell's Army passed thru Maury Co., TN. Cox had been reported by a neighbor as a Confederate spy and a squad was sent to execute him. Cox was shot down in his own yard.
Cox married Martha C. Evans 1835 in Maury Co. TN.
They had one son, Dr. Henry Smith Cox, who was a Surgeon Co. A, 9 TN Cav (Gnatt's) and the 1st Ark Sharp Shooters and another son, William James Cox, who served in the 3 TN Inf.
Does any of this agree with what you remember?