A Time for Killing (1967)

After Capt. Dorrit Bentley (George Hamilton) and his fellow Confederate troops escape from a Union prison, Maj. Wolcott (Glenn Ford) sets out to recapture the fugitives. As protection, the Southern escapees abduct Wolcott's lovely fiancée, Emily Biddle (Inger Stevens), and head toward Mexico. On their way to the border, they kill a Northern messenger bearing word that the Civil War is over and keep this information to themselves, resulting in more conflict with Union soldiers.