Master Sergeant Vann was a member of Company C, 1st Battalion, 21st Infantry Regiment, 24th Infantry Division. He was taken Prisoner of War while fighting the enemy in South Korea on July 5, 1950, forced to march to North Korea on the "Tiger Death March", and died while a prisoner at Hanjang-ni, North Korea on January 6, 1951. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.