Corporal Dunn was a member of Company B, 2nd Engineer Combat Battalion, 2nd Infantry Division. His unit was fighting through a roadblock that was heavily defended by enemy forces near Sonchu, North Korean. He was placed in Missing in Action status while fighting the enemy near Kunu-ri, North Korea on December 1, 1950. He was presumed dead on December 31, 1953. In 1954, the remains of Korean War service members were returned to the U.S. in an operation called "Operation Glory." These remains were unable to be identified and were interred as Unknowns at the National Memorial Cemetery of the Pacific at Honolulu, HI. The remains were exhumed in 2015 for lab analysis and by the advances in technology, established by DPAA to be those of CPL Dunn. CPL Dunn was accounted for in 2016.

Corporal Dunn's name is permanently inscribed on the Courts of the Missing at the Honolulu Memorial at the National Memorial Cemetery of the Pacific, Honolulu.