Папаша Мюллер, душка Шелленберг и русские пианисты
According to the memoirs of SS intelligence officer Wilhelm Hoettl, Schellenberg was very suspicious of Gestapo Chief Müller, whom he claimed to have evidence against by way of radio surveillance recordings (allegedly revealing Müller's plans to work with the Russians)
https://en.wikipedia.org/wiki/Walter_Schellenberg
https://en.wikipedia.org/wiki/Walter_Schellenberg