Hello. I may have some information on Urban Ehrhardt's missing relative Arthur. I am the great grandson of his cousin Oskar Ehrhardt who moved to the US with his parents in the 1890's as a baby... Oskar fought in WW1, but I bet the reason you cannot find any information on Arthur Ehrhardt is because he actually stayed in Germany, and he was a well known German WW2 SS officer. According to various sources, At his own request he was transferred to the Waffen-SS in 1944 and worked as a member of Heinrich Himmler's staff. Within the SS he rose to rank of Sturmbannführer (Major), becoming an expert in anti-espionage tactics in the Balkans. He also wrote extensively on the subject of guerrilla warfare, notably in such books as Kleinkrieg. This work has been edited by the Command and General Staff School of the United States Army in Fort Leavenworth, KA in 1936 under the title: Guerrilla Warfare. Lessons of the Past and Possibilities of the Future. However his insights into the possibility of unusual tactics being used by and against partisans were largely ignored by the Wehrmacht high command. He also served as the expert in 'Bandenbekämpfung' in the Führer Headquarters. The "Bandenbekampfung" was a program rewarding military and non military attacks on partisan resistance using his guerrilla warfare tactics. Later becoming a leading figure in the Neo-fascist movement, and being connected personally to Himmler, Hitler, and the SS, it is easy to understand why people want to forget their relation to this person.