From Eddy Portnoy, a contributing editor to the Forward who teaches Yiddish language and literature at Rutgers University, in his article "Strange Tale of Hitler's Jewish Psychic":
"The bizarre and tragic story of Erik Jan Hanussen, the famed mentalist born as Hermann Steinschneider in Vienna, is truly stranger than fiction.
A number of books and films have told the story of Hanussen, a popular figure in Europe for decades."
Dr. Walter C. Langer, a psychoanalyst, prepared a psychological profile of Hitler for the Office of Strategic Services in 1943. The profile included a reference to Hanussen: "... during the early 1920's Hitler took regular lessons in speaking and in mass psychology from a man named Hamussen who was also a practicing astrologer and fortune-teller. He was an extremely clever individual who taught Hitler a great deal concerning the importance of staging meetings to obtain the greatest dramatic effect."
"...at the top of his game, Hanussen moved his operation to Weimar’s cultural center, Berlin, where he became a major draw during the late 1920s. In addition to publishing his own newspaper, he turned his massive apartment into the Palace of the Occult, attracting the cream of Berlin society. Sprinkled into this “cream” were a number of top Nazis. Hanussen’s attraction to power was apparently stronger than his interest in his own family origins, and this would cost him dearly.
After publicly supporting Hitler and making close connections with high-ranking Nazis whose gambling habits he bankrolled, Hanussen was found dead in the spring of 1933, with a pile of Nazi IOUs. While Magida also attempts to implicate Hanussen with foreknowledge of the Reichstag fire, the reasons for his murder still remain a mystery."
There are two books written on the subject which may be of interest, The Nazi Séance: The Strange Story of the Jewish Psychic in Hitler’s Circle by Arthur Magida, and Erik Jan Hanussen: Hitler's Jewish Clairvoyant by Mel Gordon. In the Forward article, Portnoy heavily favors the book written by Gordon.