Private Koehler was a member of the 7th Infantry Regiment, 3rd Infantry Division. He was taken Prisoner of War while delaying the Chinese onslaught near Kaoch/Eang-ni, South Korea, on 25 April 1951 and died as a prisoner on 16 August 1951.

Koehler was awarded the Prisoner of War Medal, the Good Conduct Medal, the Combat Infantry Badge, the Korean Service Medal, the United Nations Service Medal, the National Defense Service Medal, the Korean Presidential Unit Citation and the Republic of Korea War Service Medal.