Investigation
The New York Police had taken note of the seemingly uncaring action of Señor Lido's companion as reported by witnesses, and took a deeper look into the dead courier's background. Although he was identified as a Spaniard, they were puzzled by the fact that the dead man's papers were in German, not Spanish; his notebook contained names and possible assignments of some U.S. soldiers; his clothes contained no labels. Moreover a check made at the hotel room yielded maps, articles on military aviation and other curious items. All of these items were turned over to the FBI.
In the meantime, another Joe K message, also followed up by the FBI, contained a panicky message about a car in New York deliberately running down and killing a certain "Phil". The BSC had informed the FBI that "Phil" had been Captain Ulrich von der Osten of the German Abwehr who had entered the United States via Japan a month prior to his "removal from circulation": he was supposed to direct the activities of a group of spies in the U.S. Based on this, the FBI was able to determine that "Señor Lido" and von der Osten were one and the same.
Piecing together a reference from "Phil's" notebook, an intercepted cable from Portugal to "Fouzie", and information from the Joe K letters themselves, the FBI was able to identify von Osten's companion as Ludwig himself. He was located and thus placed under surveillance to determine his contacts.
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