, Coyoacan, Mexico. The abduction and murder of Harte was carried out by
David Alfaro Siqueiros. Trotsky had fled to Mexico as a result of several attempted assassination and kidnapping attempts by Soviet and Stalinist agents. On May 24, 1940, a group of Soviet and Mexican, including muralist David Siqueiros and
Iosef Grigulevich, were able to gain access to Trotsky's compound. Harte had been guarding the entrance and there is some debate if Harte had let in this group or was not involved. The group fired over seventy rounds into the house but failed to kill their target. Harte was missing and believed kidnapped. Harte's body was found a month later in a well, covered in lime. He had been shot in the head. calling him the first American Trotskyist to fall victim to Stalin. An explanation provided for his murder was that he was able to identify
Iosif Grigulevich, one of the attackers, in a previous assassination attempt against Trotsky. In the article Burke notes that Trotsky wrote in the Mexican press that “The corpse of Bob Sheldon Harte is a tragic refutation of all the slanders and false denunciations made against him.” In his account of the attack Trotsky wrote that "if Sheldon Harte were an agent of the GPU he could have killed me at night and got away without setting in motion 20 people all of whom were subjected to a great risk." == Soviet agent ==