Walter Kopp was a lieutenant colonel in the Wehrmacht in Nazi Germany. After the Nazi defeat in 1945, he became the chief of one stay-behind network in West Germany, code-named KIBITZ-15. The British and US intelligence services had set up clandestine anti-communist organisations supposed to "stay-behind" in case of a Soviet invasion. Walter Kopp was described by his own North-American handlers as an "unreconstructed Nazi," and the KIBITZ-15 network as "a group with Nazi tendencies" in CIA documents released in June 2006.