Wm. S. Edmondson, Private, Company H, 29th Mississippi Volunteers, detailed as Nurse at Hospital in Bardstown, Ky. September 23, 1862, left at Murfreesboro on detail, and captured January 5, 1863, arrived at Gratiot Street Military Prison, St. Louis, Missouri January 21, 1863, Mar/Apr, 1863 Company H muster roll recorded as "Taken the oath of allegiance to the United States," no further records

M269: Compiled Service Records of Confederate Soldiers Who Served in Organizations from the State of Mississippi

Note: I suspect he was left behind at Murfreesboro to attend the wounded as a Nurse as he was previously in Kentucky. It is unusual that their are no further Federal POW records. There is no record of him after January 21, 1863. How his company gained the intelligence that he took the Oath is a mystery unless one of his comrades returned with this information.