Private First Class Marquez was a member of Company L, 3rd Battalion, 38th Infantry Regiment, 2nd Infantry Division. He was seriously wounded by the enemy in South Korea on September 6, 1950 and returned to duty on October 13, 1950. He was taken Prisoner of War while fighting the enemy near Kunu-ri, North Korea on November 28, 1950 and died while a prisoner on January 20, 1951. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.