Hitler transferred his headquarters to the Führerbunker ("Leader's bunker") in Berlin on 16 January 1945, where he (along with Bormann, his secretary Else Krüger, and others) remained until the end of April.
In 1944, Planck's son Erwin was arrested by the Gestapo following the attempted assassination of Hitler in the 20 July plot. He was tried and sentenced to death by the People's Court in October 1944. Erwin was hanged at Berlin's Plötzensee Prison in January 1945. The death of his son destroyed much of Planck's will to live.