The New York Times obituary of Mark Twain included the following paragraph.
Does anyone know the source for the particulars of the enlistment, capture,
and parole?
His experience as a Confederate soldier was brief and inglorious. Hardly had
he enlisted before he was captured. Released on parole, he broke the parole
and returned to the ranks, and soon was recaptured. He was in imminent peril,
for recognition meant immediate and ignominious execution, but he got away,
and determined never to take the risk again
Dennis Kelly