The FBI released in PDF form its file on the investigation they did into the murder of Leon Trotsky. They were interested in the true identity of the assassin, known then as Jacques Mornard, and whether tracing his contacts in the United States could reveal any Russian spies, traitors or accomplices. Of interest is the mention of the name Henry Schnautz in a memo from J. Edgar Hoover in June 1942.
Sylvia Ageloff was the girlfriend of Trotsky's assassin. Though she was unaware that her handsome boyfriend was actually plotting to kill Trotsky, her notoriety caused her two years later to live in New York under an assumed name and quietly teach a kindergarten class. The FBI tracked her down in spring 1942, hoping for some new information. The report of her interview mentioned that when news of the assassination came, she was having dinner with a Trotsky guard named Otto Schuessler. That is the page 10 (reproduced here - also page 11) that Hoover refers to in his memo. The sharp-eyed Hoover also has another case before him, Amtorg Trading Corporation Espionage, that also mentions two Trotsky guards, Otto Schuessler and Henry Schnautz. These men, according to the report, were in the United States in February and possibly still in New York. This information comes from an unnamed man in the Communist party who is a friend to a man who works in the Amtorg Corporation who tells an unnamed informant. The Amtorg Corporation was a Soviet trade company, and a known front for Soviet spies, which Hoover knows because he is investigating it.
The FBI apparently does not realize there is a war between Stalin and the Trotskyists. Information about Trotskyists that comes from the same source that killed Trotsky apparently does not trigger a consideration of motive. The report goes on further to say that this unnamed third hand source informs the FBI that these two men were involved in the Rubin case, and the State Department knows all about it. This case involved the movement of Russian spies, in 1938, who are all going to be Stalinists, and the falsification of passports to facilitate their movement. An unnamed New York communist tells a man in a Russian spy front who tells an unnamed informant who tells the FBI that the information is good because the State Dept knows all about it. The New York agent that receives Hoover's memo simply summarizes the information in the Amtorg file for the benefit of being included in the Trotsky Assassination file.
Of course, Schuessler and Schnautz were both German names in 1942. At
the time Henry Schnautz was said to be in the United States, February
1942, he was in Mexico wooing Esperanza, and even making a recording with
her to send home to his folks. In 1938 when he was supposedly involved
in an international spy ring, he was at home in Evansville raising farm
animals and working as a carpenter. These are the same two men who previously
in Sept 1941 in newspapers all over America had been wildly accused of
plotting to kill Mornard while in the custody of the Mexican police. Trying
to assassinate their prisoner would clearly have constituted a serious
crime to the Mexican police, but the day after that report came out, Henry
attends a movie with Esperanza. There was a Soviet misinformation campaign
that obtained the names of Schnautz and Schuessler and used the gullibility
of the press and J. Edgar Hoover.
vault.fbi.gov/leon-trotsky/leon-trotsky-part-3-of-5/at_download/file (relevant pages are 54, 64, 71)