Sergeant Mueller was a member of Battery D, 82nd Anti-Aircraft Artillery (Automatic Weapons) Battalion, 2nd Infantry Division. He was taken Prisoner of War while fighting the enemy near Hoensong, South Korea on February 13, 1951 and was killed by a guard on May 3, 1951. His remains were not recovered at the time. Through the work of the Defense POW/MIA Accounting Agency, the remains of Sgt. Mueller were accounted for in 2017. His name remains permanently inscribed on the Courts of the Missing at the Honolulu Memorial.