Felix Sommerfeld worked closely with German Naval Attache Karl Boy-Ed through the fall of 1914 and in the spring of 1915. His regular intelligence reports to the naval attaché attest to Sommerfeld’s job description as a German naval intelligence agent. It is highly unlikely to assume that Sommerfeld acted without approval from Boy-Ed when he took apart the Huerta plot to re-enter Mexico with Pascual Orozco and Manuel Mondragon in June 1915. Franz Rintelen, the self-styled "Dark Invader" (the title of his bestselling book about his time in World War I), sent to the U.S. to cause labor unrest and sabotage allied munitions ships, supported the Huerta plot against the wishes of his superiors in the Secret War Council. 

Franz Rintelen's passport photo from July 1915. The mustache appeared only for the purpose of the photo.

Franz Rintelen's passport photo from July 1915. The mustache appeared only for the purpose of the photo.

When Rintelen inserted himself into Mexican affairs, a much larger and much more effective German clandestine project was under way. Sommerfeld, whom the American government considered an honest broker had personal access to the highest levels of the Departments of Justice, War, and State. His connections to the American business elite greatly exceeded those of Franz Rintelen. As a result he undertook the most ambitious German project of the period: Create a war between the United States and Mexico through the manipulation of U.S. government officials, American businesses, and the only real power in Mexico to cause this war, Pancho Villa. Sommerfeld proposed to create an intervention in Mexico to the German admiralty through Bernhard Dernburg on May 10, 1915. “He [Sommerfeld] is completely sure that an intervention of the United States in Mexico can be provoked… let Mr. Sommerfeld through me [Dernburg] have a clear ‘yes’ or ‘no.’” When Sommerfeld received a clear “yes,” Rintelen stood in the way.

Sommerfeld took him out without hesitation. He leaked Rintelen’s identity to James F. McElhone of the New York Herald on May 17, two weeks after Sommerfeld went to the border, and the week after he conferred with Lindley Garrison, the Secretary of War. McElhone’s boss was Editor-in-chief William Willis, one of Sommerfeld’s closest friends. Willis not only published his reporter’s scoop on the German agent, but also reported Sommerfeld’s information to the Chief of the U.S. Secret Service, William Flynn. The New York Sun carried an article on May 26, mentioning a mysterious German agent named “Hansen” (Rintelen’s alias). Not knowing how he had been identified, Rintelen closed his office and moved in with his business associate Andrew Meloy and Frederico Stallforth at 55 Liberty Street.

Sommerfeld reportedly was a frequent visitor there. According to witnesses, he not only watched Rintelen’s every move, but also “advised” him. Rintelen had presented Sommerfeld a letter of introduction from Peter Bruchhausen. Bruchhausen, a German commercial attaché attached to the legation in Argentina, was Sommerfeld’s intelligence handler in Mexico between 1911 and 1913.

As the American secret service began to close in on Rintelen, the German agent himself participated in his own downfall. Rintelen had contracted the publicity agent, John C. Hammond, for $10,000 to spread propaganda against the Allies as early as the end of April. The effort to show Bernhard Dernburg and the others in the German Press Office how propaganda was done backfired badly. Hammond reported Rintelen’s identity, as well as his activities, to President Wilson’s secretary, Joseph Tumulty. Rintelen also blundered in his social activities. He invited Anne L. Seward, a young and pretty schoolteacher who he knew from Berlin, on several dates in the first week of June. Rintelen spoke of “unlimited funds” at his disposal and made disparaging remarks about the “policy of the United States and the action of the President,” in order to impress her and other dinner guests. The niece of former Secretary of State William Seward found “the actions and general conduct of Captain Rintelen… so suspicious that… she determined to and did write the President upon the subject.” This letter, as well, went to President Wilson’s secretary, Joseph Tumulty. 

Rintelen had become a tremendous liability for the Secret War Council in New York by the time the Huerta affair came to light. British and American agents began to hone in on his location and activities. French police discovered the first German-made “cigar” bombs on the SS Kirk Oswald in Marseilles on May 10. The New York Bomb Squad was hot on the heels of Rintelen’s sabotage team. Likely upon the request of his direct superior, Karl Boy-Ed, the German Admiralty issued an order for Rintelen’s recall on July 2. A huge strike at Bridgeport, financed through Rintelen began on July 15 and aroused further suspicions about this mysterious agent in New York. Heinrich Albert “lost” his briefcase in the New York “El” on July 24, exposing most intelligence operations the Secret War Council was conducting.

The pavement was getting too hot for Rintelen. Without the ability to obtain a new passport, the agent booked a voyage back to Europe on the SS Noordam. He had decided to use the Swiss passport with which he had come to America. Meloy, his wife, and his secretary joined the German agent on his trip. Even then, on the voyage back to Europe, Rintelen could not keep his mouth shut and aroused suspicions from other passengers. British patrols took “The Dark Invader” off the ship during a routine check at Ramsgate on August 13.

Initially able to successfully hide his true identity under questioning, he caved after a few days. The British government interned him as a prisoner of war until 1917, when the American government won his extradition. Frederico Stallforth alluded to the real attitude in the Secret War Council concerning the Huerta-Orozco-Mondragón plot in a report to Heinrich Albert in the middle of August. Celebrating the fact that Meloy had accompanied Rintelen to Europe, Stallforth wrote, “All that which might have been especially suspicious has vanished and we have put out of the way all relating to the Mexican business… Perchance [sic] you will decide… to hold our friend M[eloy] over on some pretext or other so that he will not again make such a furor [referring to the discovery of the Huerta plot] here. You can imagine how well everything is going here since he [Meloy] has been eliminated from this stage [and gone to Europe].”

Half-hearted German efforts to affect a prisoner exchange for Rintelen in 1918 did not work, mainly because a few months after his arrest in England the German government, through Ambassador Count Bernstorff, disavowed him. When Rintelen came back to the U.S. in 1917, the war between Germany and the United States he had so carelessly provoked was in full swing. Since his offenses occurred in the neutrality period, New York courts convicted Rintelen of several felonies and passed sentences aggregating to four years of incarceration for procuring a false passport, conspiracy, firebombing ships, and causing labor unrest. The Huerta plot did not figure into his conviction. There simply was not enough evidence of a German-Mexican conspiracy.

Read the entire story of the German sabotage campaign in The Secret War on the United States in 1915.