KF Ritter, published a 2006 memoir on the life of her mother - Aurora: An Alabama school teacher in Germany struggles to keep her children during WWII after she discovers her husband is a German spy.

Admiral Wilhelm Canaris, the head of the Abwehr, instructed Ritter to contact a former spymaster he knew from the first World War who was living in New York, Fritz Joubert Duquesne.

[3][page needed][4][5] Everett "Ed" Minster Roeder, another German agent in the U.S., worked for the Sperry Gyroscope Company of Brooklyn as an engineer and designer of confidential materials for the U.S. Army and Navy.

[8][dead link‍][6] Once the FBI discovered through Selbold that Duquesne was again in New York operating as a German spy, director J. Edgar Hoover provided a background briefing to President Franklin Roosevelt.

[13] Duquesne also described sabotage techniques he had used in earlier wars such as small bombs with slow fuses he could drop through a hole in his pants pocket, and he commented on where he might use these devices again.

[13] On 28 June 1941, following a two-year investigation, the FBI arrested Duquesne and 32 Nazi spies on charges of relaying secret information on U.S. weaponry and shipping movements to Germany.

[8][dead link‍] On 2 January 1942, less than a month after the U.S. was attacked by Japan at Pearl Harbor and Germany declared war on the United States, the 33 members of the Duquesne Spy Ring were sentenced to serve a total of more than 300 years in prison.

[15] In a 1942 memo to his superiors, Admiral Canaris of the Abwehr reported on the importance of several of his captured spies by noting their valued contributions, and he writes that Duquesne "delivered valuable reports and important technical material in the original, including U.S. gas masks, radio-controlled apparatus, leak proof fuel tanks, television instruments, small bombs for airplanes versus airplanes, air separator, and propeller-driving mechanisms.

[22] Ritter arranged for Owens to receive the most up-to-date training in German spycraft, so he could report detailed information on airfields, factories & special devices used by the RAF.

[25] Owens was visited in his cell on 8 September by MI5's Major Thomas Argyll Robertson (Tar), who proposed his wireless set should be brought in and used to re-establish contact with Germany, but this time it would be under MI5's control and direction.

Faced with the stark reality of the penalties meted out for spying against his own country, Owens agreed to the proposal and became Britain's first double agent whose codename was SNOW.

'[26] Owens became a key agent in Britain's Double-Cross System operated by the "Twenty [XX] Committee", a complex double-agent program whose name comes from an inter-agency board chaired by MI5 with representatives from all British intelligence services and interested departments.

In the summer of 1940, Ritter suddenly began sending Owens advance warning of the first German invasion spies via his radio transmitter which was now under MI5's control.

[28] Several former Abwehr chose to work for Britain and delivered vital information to the Allies, including details about troop movements and the keys to cracking German codes.

[31] Owens' downfall came after MI5 sent him on a mission to Lisbon in early 1941 to introduce their latest plant, an ex RNAS officer come confidence trickster, called Walter Dicketts, who worked in intelligence for the Air Ministry [32] during World War I, to meet Ritter and get himself recruited as a German spy.

Dicketts was sent back to Lisbon in June to help Ritter's assistant, George Seller to defect to Britain in return for being allowed to rejoin his relatives in the USA.

[7] Before the Second World War, Hauptmann Graf (Captain Count) László Almásy of the Royal Hungarian Air Force had lived in North Africa where he had been a desert explorer, mobility expert, and the celebrated aerial discoverer of the Lost Oasis of Zerzura (the subject of the later novel and film, The English Patient).

[36] In 1939, Almásy published in Germany a book based on his years in North Africa - Unbekannte Sahara; mit Flugzeug und Auto in der Libyschen Wüste (English: Unknown Sahara: With Airplane and Automobile in the Libyan Desert)[37][better source needed] With an interest in forming a spy ring in North Africa, the Abwehr sent Ritter to meet with Almásy in Budapest.

[36] Ritter's Sonderkommando (special forces unit) was tasked to provide military intelligence on desert warfare to Field Marshal Erwin Rommel, extract el Masri from Cairo, and to form a spy ring in Egypt.

[38] Immediately assigned to Ritter were two pilots, a Fieseler Fi 156 Storch liaison plane, and two Heinkel He 111 medium bombers for long-distance missions.