How extensive and effective were German espionage and sabotage activities against the United States in World War II? To make generalizations is always dangerous, but certain broad conclusions may perhaps be stated at this time, subject to minor corrections in the light of future data that may be uncovered from enemy sources or that is still closely held by United States or Allied agencies for security reasons. On the side of the enemy's activity it is well-established that from a period before Pearl Harbor until the very end of the war Germany engaged in intensive efforts to obtain military, economic, and political information from the United States. In furtherance of this effort she recruited numerous secret agents to operate within the United States and established extensive espionage networks in other countries of the Western Hemisphere. In the field of attempted sabotage the activity was not comparable; the failure of the large-scale mission entrusted to the eight saboteurs who landed on the East coast in June 1942 appears to have discouraged further efforts in this direction. The German record of accomplishment did not measure up to the effort expended. As far as is known there was no enemy inspired act of sabotage within the United States during the war. On the espionage side, while Germany did from time to time obtain information relating to war production, shipping, and technical advances, it was almost always too late, too inaccurate, or too generalized to be of direct military value. It is possible that in early 1942 Germany did obtain some information that assisted in locating submarine targets, although this has not as yet been finally determined; but on the whole, after Pearl Harbor, German espionage against the United States failed to produce the information required by the High Command. This failure was due to a combination of Allied counter-measures and fatal weaknesses on the part of German intelligence itself.
The German Intelligence Services
The secret intelligence requirements of the German [Armed Forces] High Command [O.K.W.] under the Third Reich were served by a separate branch of the O.K.W. called the Amt Auslands und Abwehr (commonly referred to as the Abwehr) independent of the three service commands–Army, Navy, and Air. Each of these three maintained its own intelligence staff for the evaluation and dissemination of information obtained from both open and secret sources; but these staffs conducted no secret intelligence activities themselves. Rather they maintained liaison with the Abwehr to which their special needs for information were made known. These requests the Abwehr endeavored to meet, at the same time being engaged in the task of collecting on a world-wide scale all manner of information which could be of interest to the High Command or the individual services subordinate thereto.
The Abwehr was divided into three basic groups (Abteilung). Abt I was charged with offensive intelligence, including espionage; Abt II with sabotage and subversion; and Abt III with counterintelligence and security. Of these our principal interest lies with Abt I. This was broken down into sections having cognizance respectively over military, naval, air, and economic intelligence, plus certain technical sections. The sections were further broken down into geographical subsections, dealing with particular countries or areas. In addition to the headquarters organization in Berlin the Abwehr maintained field offices in Germany and abroad staffed by Abwehr officers. In Germany and occupied countries these field offices were referred to as Abwehrstellen (Asts) with branches thereof called Nebenstellen (Nests); in neutral countries the Abwehr office was called a Kriegsorganisation (KO) and usually acted under cover of the diplomatic mission. Organizationally the field stations reproduced the functional division at headquarters. Both headquarters and the field stations recruited, trained, and dispatched espionage agents for missions abroad. While in theory there was a rough geographical division of responsibility between the various Asts, in practice there was a great deal of overlapping. Thus while Ast Hamburg, and its subsidiary Nest Bremen, had primary responsibility for espionage against the United States there was nothing to prevent Ast Cologne or KO Spain from sending an agent to this country if it happened to recruit one it believed well fitted. This factor alone led to a good deal of confusion and inefficiency in the operations of the Abwehr. Personnel of the Abwehr included officers of the Army, Navy, and Air Force, both active and retired or reserve, and civilians recruited and commissioned directly.
Side by side with the Abwehr there existed another intelligence agency–the Sicherheitsdienst (S.D.). Originally the security and intelligence service of the Nazi Party, it came to play a more and more dominant role as an intelligence organ of the Reich until eventually it gained control over the Abwehr itself. In September 1939 the S. D. was brought together with the various police agencies of the State, including the Gestapo, to form the Reichssicherheitshauptamt (R.S.H.A.) or Central Security Service of the Reich. Through one section of the latter–Amt VI–the S.D. soon developed an interest in foreign intelligence and began dispatching its own agents abroad. At first it limited itself to political intelligence, but as the war developed it gradually extended its interests to economic and military matters, and by January 1944 was running its own espionage networks in Spain, Argentina, and elsewhere. The officials of the S.D. were virtually all members of the Nazi Party S.S.
As one phase of the rivalry between the Wehrmacht and the S.S., and also because of increasing annoyance with the failure of the Abwehr, there was a long campaign by the R.S.H.A., and particularly [Heinrich] Himmler and [Ernst] Kaltenbrunner, to gain control of the Abwehr. This was successful in the spring of 1944 when the Abwehr was finally taken over by the R.S.H.A. Some of its functions were handed over to Amt VI and Amt IV (the Gestapo) but the majority, as well as most of the personnel, were retained in a new section known as the Militaerisches Amt. Theoretically on a par with the other sections of the R.S.H.A., the MilAmt came more and more under the domination of Amt VI; after July 20, 1944, [Walter] Schellenberg, head of Amt VI, took over the MilAmt as well as a result of the execution of Col. Hansen, its former chief, for his part in the plot against Hitler's life. Thus during the last year of the war the R.S.H.A. dominated the whole field of German intelligence. In the earlier part of the war most of the agents met with abroad represented the Abwehr, but towards the end they were almost sure to be S.D. agents.
Activities Before Pearl Harbor
As early as 1936 Korvetten-Kapitaen Pheiffer, a veteran of the German Navy of World War I, who had returned to active duty as an Abwehr officer in 1935, was collecting information from the United States of interest to the German High Command. Pheiffer was in charge of the naval section of Nest Bremen and as such in a position to establish close contacts with the extensive German shipping interests centered in that port. At first he worked through the "Aussenhandelstelle," or foreign trade office, where all German businessmen going overseas were registered, interviewing returning travelers on their return for any interesting observations they might have made, especially in foreign ports. From, these casual contacts Pheiffer subsequently recruited agents for the express purpose of seeking information abroad. At the same time he was enlisting the assistance of officers of the Merchant Marine both in reporting their own observations and seeking information from contacts in foreign ports whose reports they would turn over to Pheiffer. The latter has stated the German intelligence files had become so out of date during the 1920s and early 1930s that when the period of rearmament began it was necessary to seek information of all types from abroad–much of it by no means secret–in order to compile up-to-date data. Nevertheless, Pheiffer was particularly interested in new technical developments in the fields of ship design, armament, and special equipment.
It was through one of his volunteer agents on the liner Bremen that Pheiffer made contact with the notorious Dr. Griebl, who over a period of time supplied him with information on United States aircraft. This was also the period of Fritz Duquesne, Lili Stein, Gunther Rumrich and other German agents whose activities in the United States and arrests have received such wide publicity as not to warrant further discussion. Suffice it to say that while these and other agents who operated in this country before 1939 obtained information of some value to Germany, they did not succeed in obtaining vital secrets or in establishing a widespread espionage net that was able to continue into the war years.
After the outbreak of war in Europe, and particularly after the fall of France, it became of increasing importance for Germany to obtain intelligence on the nature and extent of equipment being sent to Great Britain, data on ship sailings and the war potential of the United States. Much of this was readily available from the press and other open sources in the United States to German diplomatic personnel. To supplement these sources and evade British censorship, the Abwehr established espionage networks in Mexico and other Latin American countries which relayed information from the United States to Germany by radio and other clandestine communications.
Among the most active of these was a ring in Mexico headed by Georg Nicolaus. Nicolaus, whose activities extended from 1940 to his arrest in the spring of 1942, was a competent individual. He had served with distinction in the Germany Army in World War I, spent many years in Colombia, and returned to Germany in November 1938. In January 1939, he was re-commissioned in the Army and assigned to Ast Hanover of the Abwehr. Late in 1939 he was ordered to Mexico to organize an espionage network. During his 2 years of activity in Mexico, Nicolaus organized an extensive network which maintained contact with other groups in South America and attempted to obtain information from the United States. While technical data from United States publications was extracted or photographed and some general information obtained from contacts in the United States, again there is no evidence that Nicolaus was successful in laying his hands on any vital military secrets. He was successful in leaving behind the nucleus of an organization which was able to maintain some activities throughout the war, although this was of little value to the enemy other than its nuisance value in occupying the attention of United States counter-intelligence agencies.
During this same period–between the outbreak of war in Europe and Pearl Harbor–the Abwehr succeeded in establishing a number of espionage networks in South America. These were centered in Brazil, Chile and Argentina, with ramifications in other countries. Until their liquidation, two groups in Brazil, headed respectively by Albrecht Gustav Engels and Nils Christian Christensen, were the most important and successful. Through organizations in Brazil itself, staffed by members of the well-entrenched German colony, information was collected on British shipping and forwarded by clandestine radio to Germany. Similar information from the River Plate region collected by agents in Argentina was relayed through the Brazil stations. The Brazil group also acted as relays for information of a more general nature, including intelligence originating in the United States, forwarded by such agents as Nicolaus in Mexico, Walter Giese in Ecuador, and the so-called PYL group in Chile. The group also had its own contacts on ships between the United States and Brazil. Through use of channels along the West coast of South America and connections with Europe via clandestine radio and the Lati airline, these scattered but interrelated groups were able to escape British censorship and maintain safe and reasonably rapid contact with Abwehr stations in Hamburg, Cologne and Berlin.
During 1940 and 1941 these groups must be credited with accomplishments which were probably of considerable value to Germany. Not only did they forward a quantity of basic economic data useful to Nazi analysis, but the shipping information supplied resulted in the loss to submarines of British and Allied ships. It is of interest that Nicolaus, Engels, and Christensen were all sent out by Group I (Wi) of the Abwehr (economic espionage), but as the war progressed their activities became more and more concentrated on naval and maritime intelligence. In general this was the most successful period of German espionage in the Western Hemisphere; after Pearl Harbor the Abwehr was never able to produce intelligence on the same scale.
After Pearl Harbor
The activities of these espionage groups in Latin America had not gone unnoticed by United States and British counter-intelligence agencies, but prior to Pearl Harbor there was little that could be done about them. During the early months of 1942 active steps were taken to correlate this information, identify those agents who were still unknown, and persuade local police authorities to arrest, intern, or deport them. As a result of these efforts the leaders of the Brazilian rings were arrested in March 1942 and Germany was never again successful in establishing an effective espionage service in Brazil. Prior to their liquidation, however, the Brazilian groups had made strenuous efforts to obtain military information from the United States. One example was the recruiting of a Brazilian Air Corps officer, who was coming to this country on an official mission under the auspices of our Military Attache to visit a number of aircraft factories. Fortunately, the Office of Naval Intelligence learned of this officer's connections shortly before his departure and his trip was canceled.
In most other Latin American nations, pressure from the United States succeeded in eliminating the most dangerous German agents by mid-1942. This success was tempered by continued toleration of active German espionage on the part of Argentina and Chile. In both countries Axis agents drew their support from large resident German colonies with strong local connections, from the continuance of diplomatic relations until a relatively late date, and from the complaisance of local officials.
After the breakup of the Brazilian groups, the organization in Argentina became the most important in South America. Between January 1942 and the spring of 1945 the German espionage network in Argentina went through a number of changes some of them forced by the arrest or exposure of its agents, but was always able to maintain a nucleus from which to build anew and to continue forwarding information to Germany.
During 1942 the dominant figure was Capt. Dietrich Niebuhr, the Naval Attaché, who had as his two principal assistants Hans Napp and Ottomar Mueller, and also enlisted the services of certain individuals who had escaped from Brazil at the time of the arrests there. The activities of Niebuhr and his immediate assistants were exposed in a note handed the Argentine Government by the United States Ambassador late in 1942 and a reorganization became necessary. This was accomplished by Gen. Friedrich Wolf, the Military Attache, and Johannes Siegfried Becker, an S.D. officer sent clandestinely to Argentina from Germany in January 1943. These two had at their disposition, both for personnel and funds, agents connected with the earlier groups still at large, the facilities of the German Embassy, German firms, Spanish shipping circles, and Argentine nationalists. From these diverse elements Wolf, and more especially Becker who was an extremely able individual, succeeded in weaving a net which had threads running into Uruguay, Paraguay, Chile, and even Mexico, and maintained fairly regular communication with Germany by radio and courier.
As a result of the arrest by the British of Osmar Alberto Hellmuth, an agent on his way to Germany from Argentina, in late 1943, information on the espionage activities of this group was furnished the Argentine Government which precipitated the rupture of diplomatic relations and the arrest of some of the most active agents. Becker survived this crisis. Within a couple of months he had his organization functioning again and in June 1944, received assistance from Germany in the form of two agents landed clandestinely on the coast of Argentina from an auxiliary yawl which had crossed the Atlantic from the French coast. The network suffered further losses from arrests in August 1944, but was able to continue some activities until the very end of the war.
Closely connected with the successive groups in Argentina, there existed until February 1944 an active German espionage organization in Chile. Mention has already been made of the PYL group which was active before Pearl Harbor and maintained contacts in all the West Coast South American countries as well as with the German groups in Brazil and Argentina. This group, under the control of Ludwig von Bohlen, Air Attache of the German Embassy, received assistance from numerous individuals and firms among the large German colony in Chile. As a result of information collected by United States counter-intelligence agencies and furnished the Chilean Government by the State Department, a number of the more active agents of this group were arrested in the fall of 1942. Enough escaped, however, to permit von Bohlen to rebuild another network, known as the PQZ group. When von Bohlen was repatriated late in 1943, this group was sufficiently well-organized so that he could leave it, as well as a large sum of money and equipment, in the hands of Bernardo Timmerman, who carried it on until his arrest in February 1944.
To supplement both his own organization in Argentina and the PQZ group, Johanns Siegfried Becker established a Sicherheitsdienst network in Chile early in 1943. This was under the leadership of Heinz Lange, a veteran of German espionage in Brazil and Paraguay, assisted by Eugenio Ellinger, whom Becker sent to Chile in April 1943. These two organizations, which worked closely together, maintained contacts in Peru and Bolivia. Most of their information was forwarded to Germany via Buenos Aires, although some was sent direct via short-wave radio. As a result of widespread arrests by Chilean police in February 1944, the espionage rings in Chile were effectively smashed–not, however, before some of their members escaped to Argentina where they continued their activities.
From the above it will be seen that the Germans succeeded in maintaining an espionage organization in South America, and communications between it and Germany, throughout most of the war. In this they were assisted by local elements in both Chile and Argentina, and especially by Spanish officials and members of the crews of Spanish ships who provided continuous courier facilities.
The question may well be asked, what and how valuable was the information these agents collected and forwarded to Germany? This question can only be answered with the reservation that we can never be sure that we have the whole answer. We do know a certain amount. Much of the information was of a general nature relating to industrial production in the United States, political and economic trends, labor disputes, and exports of raw materials from Latin America. These data were not obtained by "Mata Haris" from secret sources but from the careful perusal of thousands of United States publications, both general and technical, and from systematic contacts with Latin American individuals, both official and private, who were in a position to obtain information about the United States. The results were not dramatic, but they provided the raw material which any intelligence agency needs to formulate its picture of the enemy.
Aside from this general information, there was some of more direct naval interest. The Chilean group, especially concentrated on reporting the movements of United Nations vessels along the West Coast, together with data on the antisubmarine equipment and armament of both merchant and naval vessels. Late in 1943 a report was sent to Germany from Chile, via Argentina, giving details of United States naval gunnery practice and data on certain types of torpedoes. This is believed to have been obtained either from Chileans who visited United States naval vessels, or from observations of gunnery exercises held aboard a United States cruiser off Callao in the summer of 1943 for the benefit of the President of Peru and a large party of Peruvian officials. Similarly, in December 1943, one of the German agents in Chile obtained from a Chilean Air Force officer, who had spent 9 months training at the Naval Air Station, Corpus Christi, technical details of United States aircraft construction and performance and data on naval flight instruction and training accidents.
German Agents in the United States Itself
The Germans did not limit their attempts to obtain information from the United States to the establishment of espionage nets on the periphery. Throughout the war attempts were made to establish agents within the United States itself. Speaking generally, it can be reported that these efforts failed. In most cases the agents were either apprehended before they could commence activities, or their operations were sufficiently well controlled to neutralize them. The reasons for their failure ranged all the way from carelessness–as in the case of Werner Janowski, an agent landed on the coast of [southern shore of the Gaspe Peninsula, Quebec] Canada [by U-518] early in November [9 Nov.] 1942, who was caught within a few hours through his stupidity in throwing away a box of Belgian matches in a hotel room and otherwise arousing the suspicions of civilians–to voluntary surrender on the part of the agent. Two of the eight saboteurs who landed in June 1942 gave themselves up to the Federal Bureau of Investigation and thus precipitated the arrest of the others. [On 13 June 1942, 4 agents were landed from U-584 on Amagansett, Long Island, New York; and on 17 June 1942, 4 agents from U-202 were landed on Ponte Vedra Beach, south of Jacksonville, Florida. A subsequent military trial of the 8 captured agents resulted in 6 death sentences, one life imprisonment and one 30-year sentence. On the recommendation of the Justice Department, President Truman granted executive clemency on condition of deportation to the two surviving agents who were deported to the American Zone of Germany in 1948].
Most of the cases of German espionage agents in the United States have received such wide publicity in the press that it is unnecessary to discuss them in detail. Mention of a few of them will serve to indicate that there were continued, if sporadic, attempts, on the part of Germany to place such agents. While the saboteurs' and Janowski's cases were the first to attract general attention, they were not the first agents to operate in the United States during the war. During the latter part of 1943 and early 1944, the Federal Bureau of Investigation announced the arrest of four groups of agents who had been operating independently for a considerable length of time. Ernest Lehmitz, Grace Buchanan-Dineen, and Wilhelm Albrecht von Rautter had all been recruited by the Abwehr in Europe between 1939 and 1941 and returned to the United States before Pearl Harbor. They surrounded themselves with a few assistants or subagents and forwarded reports in secret writing on shipping, war production, and other military information to cover addresses in neutral countries in Europe. The existence of all these agents first became known through Allied censorship, largely because of their use of cover addresses which were already compromised; and while in some cases it took long and painstaking research and the comparison of thousands of handwriting samples to identify them and their confederates, their reports to Germany were under the control of United States counter-intelligence agencies from a fairly early date in their active career.
The neutralization of these agents should not be interpreted as a sign of their incompetence or that of their Germany masters– except insofar as the furnishing of the same cover addresses to various agents was careless. Rather the fact that Lehmitz and von Rautter were able to live and operate in the United States in wartime for over 2 years without detection, must impress one with the need for constant vigilance, while their ultimate identification is a lesson in the relative importance of painstaking research and checking versus more melodramatic methods of counter-intelligence.
The arrests of its agents made in 1943 and early 1944 did not discourage German intelligence from sending further agents to the United States. Among the survivors of a submarine [U-1229] sunk off the coast of Maine in the summer of 1944 [on 20 August] was one Oscar Mantel, who was to have been landed on the Maine coast in order to establish himself as an agent in this country. He was an experienced intelligence agent with a history of activities in Spain and France and he had received considerable specialized training for his mission. In November 1944, the R.S.H.A. tried again. This time [on 29 November] a submarine [U-1230] succeeded in putting ashore William Curtis Colepaugh and Eric Gimpel, who made their way to Boston and New York. The former was a maladjusted American who had jumped ship in Lisbon and offered his services to the Germans, while the latter had been repatriated to Germany from South America. Within a month of his arrival, and after spending a good share of the funds advanced him, Colepaugh had surrendered. Then as a result of the interrogation of Colepaugh, Gimpel was arrested before he could begin to discharge his mission. [They were found guilty and sentenced to death in a military trial, but President Truman subsequently commuted the sentence.] As far as is known this was the last attempt of German Intelligence to send agents to the United States during the war; although as late as September 1945 a German who had been trained for a mission to the Western Hemisphere, and who was attempting to reach South America under false papers, was removed from a Spanish ship at Trinidad.
In addition to employing agents resident in the Western Hemisphere, the Germans utilized members of the crews of Spanish and Portuguese ships to observe shipping in the United States ports and to report on convoys sighted at sea. These seamen were also used to buy numerous American magazines which were then studied in Lisbon or clipped for use in Germany. From these sources, which represented exploitation of perhaps unavoidable loopholes in United States security rather than positive espionage, the Germans obtained information of over-all intelligence value, but little of immediate operational significance.
Objectives of German Espionage
Throughout the war the Germans sought military, political and economic information of any and all types, and the broad assignments given agents may well be one reason for the failure to obtain specific data of high quality. At the same time, certain subjects received special emphasis. Among these were data on aircraft production and types, and information on anti-submarine devices. Beginning in late 1942 or early 1943 the Germans realized that the success of their submarine arm, in which they placed so much hope, was threatened by Allied anti-submarine devices and techniques, and information on these became the priority intelligence requirement and remained so until the end of the war. The information was sought from all the sources discussed above and in the neutral countries of Europe as well. Fantastic sums were offered on the Lisbon espionage market–and were sometimes paid for reports invented by the agents themselves. It is a source of satisfaction that interrogation of German intelligence and naval officials indicates that they never succeeded in getting the vital information.
Reasons for Failure of the German Intelligence Services
In conclusion one may speculate as to the reasons why the German intelligence services failed to produce results more in keeping with the effort expended. The first reason seems to be over-organization, with conflicts and duplication between the Abwehr and R.S.H.A. and within the two organizations themselves. The Abwehr was further handicapped by bureaucracy, lack of initiative, and corruption on the part of many of its officers, who were lukewarm Nazis at best and regarded a berth in the Abwehr as an opportunity to avoid service on the Russian front. By contrast the R. S. H. A. tended to be aggressive and imaginative, but it suffered from lack of experience and inability to evaluate information objectively. The personnel of both services was poorly chosen. The comment has often been made by Allied counterintelligence agencies that most German agents were of low grade and quality. The fault appears to have been with the initial recruiting and not with the training, although this was sometimes superficial.
Of course in spite of these weaknesses, the constant attention of the Allied agencies was required to prevent the Germans from getting information which might have been of immense value to them. Our experience showed that passive security measures, while essential, are not enough. There must be constant active counter-intelligence, in the form of both research and field work and a coordination of the two, directed toward increasing our knowledge of the enemy's intelligence organization, methods, capabilities and personnel.
For Further Information - A Select Bibliography:
Bishop, Eleanor C. Prints in the Sand: The U.S. Coast Guard Beach Patrol During World War II. Missoula MT: Pictorial Histories Publishing Co., 1989. [The landing of 4 Abwehr agents on Amagansett, Long Island, New York, from U-584, and 4 agents on Ponte Vedra Beach, south of Jacksonville, Florida from U-202 in June 1942, are described on pp. ix-x; the November 1944 landing of agents Gimpel and Colepaugh in Maine from U-1230 is described on pp. 30-31.].
Blair, Clay. The Hunted, 1942-1945. vol. 2 of Hitler's U-Boat War. New York: Random House, 1998. [The unsuccessful mission in August 1944 to land an agent from U-1229, the agent's capture after the sinking of the submarine, and the Navy's decision to treat him as a prisoner of war rather than turn him over to the FBI is described on p. 644. For the story of the two agents landed in November 1944, see pp. 646-647.].
____. The Hunters, 1939-1942. vol. 1 of Hitler's U-Boat War. New York: Random House, 1996. [For the landing of agents in June 1942, and their subsequent fate, see pp. 603-606. Also mentioned is the arrest of 14 friends and relatives of the agents, and the conviction of 10 of them. President Truman later commuted the sentences of the friends and relatives.].
Breuer, William. Hitler's Undercover War: The Nazi Espionage Invasion of the U.S.A. New York: St. Martin's Press, 1989. [See the appendix on pp.321-324, "Espionage Agents Convicted in the United States, 1937-1945."].
____. Top Secret Tales of World War II. New York: John Wiley & Sons, 2000.
Cohen, Gary. "The Keystone Kommandos." Atlantic Monthly 289, no.2 (Feb. 2002): 46-59. [Includes two photos of the military tribunal, mug shots of the eight prisoners as well as short biographies, information on the execution and burial of the condemned, and an anecdote about George Dasch's later years and his friendship with Charlie Chaplin.].
Conn, Stetson, Rose C. Engelman, and Byron Fairchild. Guarding the United States and Its Outposts. Washington DC: Office of the Chief of Military History, 1964. [For the June 1942 landings see pp. 99-100.].
Dasch, George John. Eight Spies Against America. New York: R.M. McBride Co., 1959.
Farago, Ladislas. The Game of Foxes: The Untold Story of German Espionage in the United States and Great Britain During World War II. New York: David McKay Company, 1971.
Gimpel, Erich with Will Berthold. Spy for Germany. London: Robert Hall, 1957.
Hadley, Michael L. U-Boats Against Canada: German Submarines in Canadian Waters. Kingston and Montreal, Canada: McGill-Queen's University Press, 1985. [Includes the story of Werner Alfred Waldmar von Janowski who landed from U-518 in Canada on 9 Nov. 1942, as well as the story of the unmanned German weather station established by U-537 in northern Labrador on 22-23 October 1943.].
Hilton, Stanley E. Hitler's Secret War in South America 1939-1945: German Military Espionage and Allied Counterespionage in Brazil. Baton Rouge: Louisiana State University, 1981.
Jong, Louis de. The German Fifth Column in the Second World War. Chicago IL: University of Chicago Press, 1956.
Kahn, David. Hitler's Spies: German Military Intelligence in World War II. New York: Macmillan, 1978. [The story of the November 1944 landing of two agents, including a map of their landing place in Frenchman Bay, is in Chapter 1, "The Climax of German Spying in America," pp. 2-26. Useful footnotes are on pp. 553-554].
Lardner, George, Jr. "Nazi Saboteurs Captured." The Washington Post Magazine (13 Jan. 2002): 12-16, 23. [Includes photos of the eight saboteurs landed in June 1942, information on their trial before a military tribunal, the execution of six of them by electric chair, and the fate of George Dasch after his return to Germany in 1948.].
Morison, Samuel Eliot. The Atlantic Battle Won, May 1943 - May 1945. vol. 10 of History of United States Naval Operations In World War II. Boston: Little, Brown and Company, 1960. [ See pp. 326-327 for brief information on the unsuccessful attempt to land Mantel from U-1229; and pp. 330-331 for the landing of agents in November 1944.].
____. The Battle of the Atlantic, September 1939 - May 1943. vol.1 of History of United States Naval Operations In World War II. Boston: Little, Brown and Company, 1947. [See p. 200 for brief information on the June 1942 landings.].
Noble, Dennis L. The Beach Patrol and Corsair Fleet. Washington DC: Coast Guard Historian's Office, 1992. [See pp. 8-11 for the story of the agents landed in June 1942 on Long Island.].
The Oxford Companion to World War II. New York: Oxford University Press, 1995. [See "Latin America at War" for a summary of Latin American activities not emphasizing espionage; and "Spies," which includes a section on German intelligence in the Western Hemisphere.].
Rachlis, Eugene. They Came to Kill: The Story of Eight Nazi Saboteurs in America. New York: Random House, 1961.
Whitehead, Don. The FBI Story. New York: Random House, 1956. [For the landing of German agents in 1942 and 1944, see pp. 199-206.].
Wighton, Charles and Gunter Peis. Hitler's Spies and Saboteurs: Based on the German Secret Service War Diary of General Lahousen. New York: Henry Holt and Company, 1958. [Lahousen was head of the Abwehr's Abt. II, which was responsible for sabotage.].
Willoughby, Malcolm F. The U.S. Coast Guard in World War II. Annapolis MD: United States Naval Institute, 1957. [The landings of German agents is discussed on p. 46, within a chapter on the Beach Patrol.].