The Central Information Agency on Prisoners-of-War ( Zentralauskunftsstelle fÃ 1\/4 r Kriegsgefangene ) had a staff of 3,000 , the card index tracking prisoners contained 45 million cards ( more than 6 times as many as world war 1 ) , and 120 million messages were exchanged by the Agency . The Central Information Agency on Prisoners-of-War ( Zentralauskunftsstelle fÃ 1\/4 r Kriegsgefangene ) had a staff of 3,000 , the card index tracking prisoners contained 45 million cards , and 120 million messages were exchanged by the Agency .