A few days before his murder on August 20, 1940, Trotsky finished writing a lengthy article, “The Comintern and the GPU,” dealing with the attempt on his life in the Siqueiros raid on May 24. The article was for submission before the Mexican courts as well as for general distribution. As with the Dewey Commission of Inquiry into the Moscow Trials, it is an exacting and devastating answer to the Stalinist lie machine and places responsibility for the May attack where it belonged—on the Stalinist regime and its secret police, the GPU. Trotsky’s dedication to the completion of this article interfered with and delayed his work on the biographies of Lenin and Stalin. Natalia, his widow, has recounted the supreme efforts he made to complete his investigation into the May attack. She wrote:

At the same time, Lev Davidovich was taking part in the conduct of the investigation of the case of May 24. Its slothful pace worried LD exceedingly. He followed the developments patiently and tirelessly, explaining the circumstances of the case to the court and to the press, making superhuman efforts to force himself to refute the self-evident and hopeless lies or malicious equivocations, doing all this with the intense perspicacity peculiar to him, and not allowing a single detail to escape his notice. He attached the proper significance to every single thing, and wove them into a single whole.

While Trotsky was conducting his investigation into the Siqueiros raid, so was the US State Department. As we have already shown, a confidentially coded message was sent to the American consul in Mexico City on May 25 asking him to make the fullest inquiry into the activities of the missing American, Robert Sheldon Harte from New York. Acting on State Department instructions, US consul George P. Shaw sent his aide, Robert G. McGregor, Jr., to Coyoacan on May 24, 1940, hours after the armed Stalinist raiders broke into Trotsky’s house firing over 300 rounds and setting off incendiary bombs. In his covering letter to Washington, Shaw said:

I have the honor to refer to my telegram to the Department, May 24, 1940, noon, concerning the disappearance of Mr. Sheldon Robert Harte, who had been acting as a secretary, really a bodyguard, of Leon Trotsky at the time the latter’s house was assaulted by a band of armed men early in the morning of May 24, 1940, and who disappeared at the time, presumably kidnapped. Reference is made also to my conversation with Assistant Secretary Adolph A. Berle, Jr., and to telephone conversations between Mr. Herbert S. Bursley and Charge d’Affaires Pierre de L. Boad in my presence on the same subject. This matter was first brought to my attention by Mr. Charles Cornell, who came to the Consulate General to report the disappearance of Mr. Harte. The telegram to the Department was based on his statement and I immediately delegated Consul Robert G. McGregor, Jr. to accompany Mr. Cornell to Trotsky’s residence to verify the statements made and to ascertain any other interesting facts available.

Mr. Jesse S. Harte, the father of the young man who has disappeared, called me on long distance telephone and stated he was coming to Mexico City by airplane, which he did, arriving at 5:45 p.m. yesterday. The Embassy received a telegram from a Mr. Drew Pierson, recommending Mr. Harte, and asking that all proper facilities be extended to him. Mr. Harte claimed an acquaintance with both Mr. Berle and Mr. J. Edgar Hoover. It is understood that an FBI contact in Mexico City received a call from Washington on this subject, and that it probably originated from the source just mentioned.

This office addressed an official communication to the Chief of Police of the Federal District which was delivered immediately by hand asking that all proper steps be taken to apprehend the presumed abductors and to recover the missing American citizen unharmed. The Federal Judicial Police were also approached and two men were assigned to the case, who have been constantly with Mr. Harte since his arrival. Every proper step is being taken to keep this matter constantly before the officials and to aid Mr. Harte in every proper way in the investigation of this case.

The Embassy has received the Department’s telegram instructing it to bring the matter to the attention of the Foreign Office verbally, and this was done this morning. Attached hereto is a memorandum written by Consul McGregor based upon his conversation and observations in Trotsky’s residence on the morning of the incident. The various political factors in the case bearing upon the international situation will be reported in detail in an air mail despatch tomorrow.

Respectfully yours,
Geo. P. Shaw
American Consul.

McGregor’s “confidential memorandum” to Shaw reads:

Acting under your instructions and accompanied by Mr. Charles Cornell, whose family lives at 2179 Tupmans Street, Fresno, California, I accompanied the latter in his car to the residence of Mr. Leon Trotsky, in Coyoacan, in order to gather all available information with regard to Mr. Sheldon Harte, alleged to be an American citizen, who was kidnapped early this morning in connection with an attempt to assassinate Mr. Trotsky. The grounds on which Mr. Trotsky’s house is located were surrounded by police officers and plainclothes men, and many newspaper men were in evidence. Mr. Cornell showed me over the premises, indicating how the attempted assassination was made. He explained that there are five foreigners always in attendance as aides and guards to Mr. Trotsky.

Four of those so assigned at the present time are American citizens who, besides Mr. Cornell, are Mr. Harold Robins, of Detroit, Michigan, Mr. Jake Cooper, of 2518 Portland Avenue, Minneapolis, Minnesota, Mr. Walter Ketley, of New York City, in addition to a German by the name of Otto Schussler and Mr. Harte. At the time the attempt was made, namely 4:30 this morning, Mr. Harte was on guard and located in a wooden shelter attached to the garage. It would appear that the assassins, after first gagging the police on duty outside the property, demanded entrance at the front wooden door giving access to the property. It is presumed that Harte opened the door and was seized by the persons seeking to gain admittance. He did not cry out nor did he shoot. It is presumed that he was kidnapped by the assassins after perpetrating their attack. Both cars belonging to Mr. Trotsky’s guards, a Ford and a Dodge, were used by the assailants in a getaway. The Ford was found three blocks away in a ditch, and the Dodge, with Texas plates, is still missing. Presumably Mr. Harte was taken in one of these two cars.

I examined the room assigned to Mr. Harte and found a letter from his father, Jesse S. Harte, President of the Intermediate Factors Corporation, 1450 Broadway, New York City, telephone Wisconsin 70251. According to Mr. Cornell, Harte was kidnapped while wearing khaki riding breeches and brown riding boots, a sweater and a brown coat. A “zarape” which he used while on watch was found in the garage near where the Dodge is customarily parked. Harte is described as a boy about 25 years of age, 5 feet 11 inches tall, with sandy hair and blue eyes. He speaks French and English and broken Spanish. He is stated to have been in Mexico six weeks.

I entered the house proper and was confronted by Mr. Trotsky. He was most polite and talked with me in his office for about ten minutes. He said he had no doubt that the assassination was attempted by Stalinist agents and that he had hopes that Harte would return unhurt, because he knew that agents of the GPU were most reluctant to kill anyone unless it was absolutely essential. He said that he decided shortly after taking up residence in Mexico to use only non-Mexicans as his helpers and guards in order to avoid any possibility of persons in his entourage engaging in Mexican politics.

For this reason practically all of the persons so employed have been American citizens who come here as tourists and stay on at his request to the Ministry of “Gobernacion.” He said all this was known and acquiesced in by the Mexican police authorities. I explained that my interest in the matter was to seek means whereby Harte could be rescued and in this connection to cooperate fully with the Mexican police. I added that personally I wished to congratulate him on his escape. Mr. Trotsky was not in the least excited and was most pleasant and cooperative, taking me himself to the room where Harte’s effects were found and escorting me through the house, where evidence of the shooting was widespread.

The attackers had used machine guns, one from Trotsky’s study adjoining his bedroom, bullets from which perforated the connecting door, and another from the garden, which shot through the double doors and sprayed the head of the beds upon which Mr. and Mrs. Trotsky were sleeping. There was evidence that at least one shot had been fired point blank into the pillow on Trotsky’s bed. Trotsky explained that he escaped by rolling onto the floor and huddling with his wife in a corner of the room. As they retreated, the attackers threw two home-made incendiary bombs into a dressing room adjoining the bedroom. In this room the floor, walls and furniture were charred, and Trotsky said that his wife moved immediately into that room and extinguished the fires with a blanket.

Mr. Trotsky explained that the Mexican police authorities had been extremely prompt, obliging, and thorough in the examination they had made of the premises up to the present time.

He asked that the Consulate General’s representations in connection with Harte take into account the susceptibility of the Mexican official to interference from outside sources. I assured him that our endeavors would be made to cooperate with the police authorities with due and customary regard to the rights appertaining to this branch of the Mexican Government.^[1]

It may be interesting to note that Mr. Otto Schussler, the German in attendance upon Mr. Trotsky, is alleged to be a very old friend of his, he having spent a year with Trotsky when he was exiled in Turkey, and continuously in touch with him since then. Schussler is short in stature, blond, Jewish, and speaks English with a thick, broken accent. He lives on the premises with his wife and according to Mr. Cornell is engaged in collaborating in some of Trotsky’s writings. I gathered that the others are employed more as guards, because I saw the regular schedule of watches which they maintain and from the fact that all of them are armed and carry sets of instructions for just such emergencies as happened. I returned to the office at 1:30 p.m.

Robert G. McGregor, Jr.

On May 27, 1940, McGregor had a second discussion, this time with one of Trotsky’s guards, Walter Ketley. He reported to the embassy:

In connection with conversation I had with Mr. O’Rourke (Ketley) this afternoon, I asked him if it was not possible that the persons who attacked Mr. Trotsky in his house last week might not be interested in acquiring the archives, perhaps having knowledge of the fact that they were to pass into the hands of Harvard University. He said that the idea had occurred to him as well as to Mr. Trotsky in view of the fact that there is contained in the articles considerable valuable information regarding Mr. Stalin which the latter had long desired to get his hands on.

With regard to the disappearance of Harte, O’Rourke said that he believed the person who demanded entry into the premises and thereby gave access to the grounds to the attackers was probably a friend of Harte’s. He said that this would explain why Harte did not take the precautions which they were all trained to take with regard to the admission of nocturnal visitors. He said that he was sure that Harte was not a party to the crime because he said that all the guards employed by Trotsky were sent here after very careful observance of their activities by members of the Party in the United States, and that Harte would have had to be a superb actor to have constantly concealed the intention for which he was sent, and that he did not believe the boy to be capable of masquerading as a Trotskyist, with all of the careful observation to which Trotsky’s aides are subjected.

His memorandum was sent under a “strictly confidential” seal to Washington with the attached comments of Consult Shaw. He wrote:

A memorandum of Mr. McGregor’s conversation with Mr. Ketley is attached hereto. It is desired to point out that Mr. Ketley had probably been instructed by Trotsky to say that he did not believe that the missing Mr. Harte was a traitor to Trotsky’s cause. However, it is pointed out that this feature was the principal point made by this morning’s press in the discussion of the case. In fact it was stated that the police strongly suspect Mr. Harte of being a Stalinist. This is probably based upon the reported fact that he had a picture of Stalin in his quarters in New York City.

Respectfully yours,
Geo. P. Shaw

Another “strictly confidential” note was air mailed to Washington on May 28, four days after the attack. It centered on the embassy’s early findings about the missing guard, Sheldon Harte. Shaw told his superiors in Washington:

I have the honor to refer to my air mail despatch No. 11 dated May 27, 1940 and to refer to the statement that when Mr. Sheldon R. Harte left New York City about April 3 or 4, 1940, he told his parents that he was coming to Mexico to join a Mr. Williams in a business venture. It is known that he arrived in Mexico City on April 7 and went directly to the house of Leon Trotsky as is now evident had been arranged.

Mr. Harte received all of his mail at the office of the Wells Fargo Express Company and a check had revealed that at the time Mr. Harte arrived there was also a Mr. Frederick Allan Williams of New York City, a man about 32 or 33 years of age, accompanied by a Mr. R.W. Ovington, about 22 or 23 years of age, who were receiving their mail at Wells-Fargo at the same time. This may be merely a coincidence but these two men were in Mexico City travelling through the surrounding country from the first part of April to about May 8 or 10. When they departed they asked that the mail for both of them be forwarded to New York City in care of Mr. R.W. Ovington at 14 Fifth Avenue. It is believed that this address is near the place young Mr. Harte maintained his quarters and where he did his writing for radical papers. It is thought that the Department may care to investigate the persons named or the address given.

The press this morning quoted the elder Mr. Harte as stating that there was a picture of Stalin prominently displayed in the quarters of his son in New York City. It appears that the father had never been in these quarters but obtained the information through his son-in-law, Mr. Morton Wild of Simon Wild and Son, 14 East Thirty-Second Street, New York City. It would be helpful to this office if the results of any investigation of Messrs. Williams, Ovington or Wild could be transmitted briefly to it by air mail.

The morning papers carry a statement to the effect that George Mink^[2] is in California. A digest of the press of May 27, 1940 is attached hereto. Mr. Jesse S. Harte, father of the kidnapped boy, is departing for New York by airplane tomorrow, May 29, 1:20 p.m. This fact is being kept from the press.

Respectfully yours,
Geo. P. Shaw
American Consul

On July 25, 1940, two months after the raid, Shaw sent Despatch No. 162, strictly confidential, entitled “Transmitting memorandum of Conversation with Mr. Leon Trotsky on June 25, 1940.” McGregor had obtained the interview in June and reported verbally. It was forwarded in writing after a request from the State Department.

McGregor reported:

During a conversation with Mr. Leon Trotsky at his house this morning concerning the attempt on his life, I mentioned statements attributed to him which appeared in the press implicating Mr. Narciso Bassols.^[3] Trotsky said his statement had been misinterpreted and referred to his declaration immediately following the attempt a month ago, to the effect that David Alfaro Siqueiros and Narciso Bassols would be able to give much information concerning the attack. I told Mr. Trotsky that I had heard sometime ago that on one of his trips Bassols, when Mexican Minister to France, had endeavored to persuade President Cardenas of the desirability of expelling Trotsky from Mexico. Trotsky confirmed this information, stating that Bassols had undoubtedly received orders from GPU agents in Geneva, Switzerland.

In a strictly confidential and private manner Mr. Trotsky told me that he suspected the orders for this attempt on his life came through the Soviet Ambassador in Washington, Mr. Oumanski, who according to Trotsky is a GPU agent. Trotsky stated that lacking a diplomatic legation in Mexico, the Soviet officials in Washington maintain an agent here, who is none other than American citizen Harry Block.^[4] He pointed to Block’s article in The Nation early in June entitled “The Phantom Conspiracy” which endeavored to explain away the attempt on Trotsky’s life. Trotsky said that Block works closely with Lombardo Toledano and the CTM and while he would not go so far as to say that Toledano is a GPU agent or affiliated with the Stalinist group, he did say that Block was an extremely dangerous man and the Soviet agent in Mexico.

The chief of the guards, Harold Robins, recalls Mr. Harte’s visit to Coyoacan. Trotsky met him and tried to offer his condolences on behalf of the movement. But Harte Sr. brushed them aside. The New York Times reported on May 27, 1940, that he offered “a considerable reward” for any information leading to his son’s whereabouts. He collected his son’s belongings from his room at Coyoacan and returned to New York. On June 25, Harte’s body covered with lime was retrieved from a shallow grave in a deserted house which had been rented by Stalinist friends of Siqueiros.

No verdict can be passed on Sheldon Harte at this stage. The US State Department records do testify to the fact that he had a photograph of Stalin on the wall of his New York flat, but it could have been placed there: or it could have been a hangover from his days in the American Communist Party, though it would be a peculiar thing to keep around the house. The report, according to the State Department records, emenated from Harte, Sr.’s son-in-law, a lawyer named Morton Wild.

In a review of two books on Trotsky’s assassination published in the Fourth International in March 1949, Alfred Rosmer has this to say about Harte and his fate:

Revolutionary movements of all times and all countries have never been able to prevent stoolpigeons from infiltrating into the ranks and even into the leadership. The question involved here is one of fact. Everyone who knew Sheldon is unanimous in rejecting the idea that he was associated with the GPU while in New York or that he was bought off during his stay in Coyoacan. They are convinced that he was duped by some trick which caused his dereliction. He was new to Coyoacan. He was very young, in age, in personality, in political experience; he had lived the easy life of a young bourgeois.

Certainly it was no accident that the scoundrels of the Siqueiros gang chose him as an unwitting accomplice in the penetration of their attack. Perhaps it was a mistake to have believed him capable of fulfilling the arduous duties required of the secretaries. But then it is only too easy to criticize the American Trotskyists, on whose shoulders alone rested the onerous task of recruiting secretaries, of supervising them and assuring their maintenance. I neither pass judgment nor take issue. I simply state that in view of these facts it would be more appropriate to be more modest in passing judgment.

The head of security at Coyoacan was Joseph Hansen, now the leader of the Pabloite revisionist Socialist Workers Party. Writing about the assassination attempt in the August 1940 edition of the Fourth International, Hansen said:

Harte, member of the New York local of the Socialist Workers Party, had been in the household scarcely eight weeks. He had been selected for guard duty because of his trustworthiness and because of his willingness to take difficult assignments. His selection came as a grateful surprise to him. He was well known in the Downtown branch where he was a member of the Executive Committee. The police on duty were themselves completely taken in by the disguises of the assailants, hence it should not be surprising that an American might likewise be deceived.

It is quite possible, however, that among those who rang the bell at the door was one person known to Bob as enjoying the confidence of the household. The psychological effect of the police uniforms in conjunction with a few words from such a person: “Bob, these officials have a message of extreme importance for Trotsky,” could have sufficiently impressed Harte who had shown himself already to be of a more trusting than suspicious nature. One of the police bound outside, Ramirez Diaz, reported that Bob was marched through the doors, protesting but not struggling, his arms pinned by two of the assailants ... Why did the GPU kidnap and kill Harte? They could have tied him up as they did the police. Was it to prevent him from naming the person who tricked him from possibly identifying the assailants later in the police line-up?

In a later article, published after Trotsky’s murder, Hansen again refers to Harte and draws attention to his relationship with the assassin, Ramon Mercader, alias Jacques Mornard, alias Frank Jacson:

Jacson came to Mexico in October 1939. According to his story, he was told not to force entry into the household but to let the meeting be “casual.” He followed his instructions perfectly. For months he did not come near Coyoacan but stayed in Mexico City. When Sylvia Ageloff, his wife, who was well known to the household, came to Mexico, he did not attempt to enter the house with her. But he utilized her to become known to the Rosmers—friends of Trotsky and Natalia since 1913—who were staying at the house after bringing Trotsky’s grandson from France. Through these trusted people he became known by name to the household. Many of the guards knew him, were accustomed to admitting him for a few moments to the patio where he would wait to meet whomever he had to see. It is absolutely certain that Robert Sheldon Harte knew him and trusted him.