By 1941 Putzi, out of favor with Hitler and the Nazis, flees Germany with his young son Egon, but he is interned in Fort Henri, a Canadian prisoner of war camp at Kingston Ontario. In 1943, Hanfstaengl offered Cordell Hull to act as a political and psychological warfare adviser in the war against Germany. John Franklin Carter draws Franklin D. Roosevelt attention to the case and the offer to "work" for the American side is accepted.
Ernst Hanfstaengl: Unheard Witness. J. B. Lippincott Co, Philadelphia & New York - 1957.
Ernst (”Putzi”) Hanfstaengl: Hitler. The missing years. Eyre & Spottiswoode, London - 1957. Same text as Unheard Witness
Persico, Joseph E. Roosevelt's Secret War: FDR and World War II Espionage. Random House - October 9, 2001 p 191-194
Francis Morris Sedgwick & Hubert Merrill Sedgwick: A Sedgwick Genealogy Manuscript to about 1950 New Haven Colony Historical Society, MMS-B46 Box 6 Folders B – R; extension of the 1934 Francis Morris Sedgwick manuscript A record of descendants of Samuel Sedgwick, 1667,