#NeverGiveUpMomGwidon Damazyn was a Polish electrical engineer and amateur radio operator with the pre-war callsign SP2BD who had been arrested in 1940 and a prisoner at Buchenwald concentration camp from March 1941 . Using his pre-war radio skills, he secretly built a short-wave transmitter and small generator, hiding both inside the prisoners' movie room where guards rarely looked closely. By early April 1945, American forces were closing in on the camp. Rather than allow liberation, the SS began forcibly evacuating thousands of prisoners on deadly marches, and rumors spread that the rest would simply be executed. Damazyn looked at that hidden But as the camp's last chance to be saved. On April 8 at noon , Damazyn and a Russian prisoner named Konstantin Ivanovich Leonov sent a Morse code message prepared by the camp's underground resistance — Damazyn sent the English and German versions, while Leonov sent the Russian version . The message read simply that this was Buchenwald concentration camp, requesting urgent help, warning that the SS intended to destroy them all. Just three minutes after the final transmission, headquarters of the U.S. Third Army responded with the message: "KZ Bu. Hold out. Rushing to your aid. Staff of Third Army" . According to fellow Polish prisoner Teofil Witek, who witnessed the transmissions , Damazyn fainted on the spot after hearing the reply . Armed with rifles and one machine gun they had secretly collected from guards since 1942 , prisoners inside the camp helped drive out the remaining SS forces themselves . On April 11, 1945, at 3:15 p.m. , a detachment of troops from the U.S. 9th Armored Infantry Battalion (6th Armored Division, U.S. Third Army) under the command of Captain Frederic Keffer arrived and formally liberated Buchenwald . .