Iosif Grigulevich, a Soviet secret police operative known for his efforts in surveilling and targeting exiled political figures, was tasked with carrying out an assassination on Leon Trotsky, a key figure in the Russian Revolution and a vocal critic of Joseph Stalin. Trotsky had been living in exile in Mexico since 1940, where he continued to organize and critique the Soviet government that had branded him a traitor. Driven by Stalin's intense desire to silence dissent, Grigulevich formulated an elaborate plan to kill Trotsky in Coyoacán, a suburb of Mexico City where Trotsky lived with his family.

On the planned day, despite the complexities of infiltrating Trotsky's household, Grigulevich gained access to the compound. Armed with a handgun, he approached Trotsky under the guise of a friendly visitor. However, the assassination attempt failed when Trotsky’s guards became alerted to the intruder's intentions. In a dramatic confrontation, Grigulevich was captured, which significantly exposed the ongoing Soviet espionage operations in foreign territories against anti-Stalinist figures.

This failed assassination attempt exemplified the tense atmosphere of the time and was part of a larger campaign of violence and repression orchestrated by Stalin against former allies and enemies alike. Trotsky survived this incident but continued to face threats until he was ultimately assassinated in 1940 by another Soviet agent in August of that year. Grigulevich's attempt was a stark reminder of the Soviet Union's relentless pursuit of political enemies.