Terry,
This doesn't help with the story but I found Lafayette Roberts in the MSG. In March 1865 he's on a list of officers under Andrew Piercy (Livingston's Battalion). The webpage below says he was captured in August 1863. That "L.F. Roberts" was exchanged at Vicksburg and on his way home when he was recaptured in Christian Co. MO.

http://freepages.history.rootsweb.ancestry.com/~jrbakerjr/partisans/lafayetteroberts.htm

Ken