Walter Germanovich Krivitsky (Ва́льтер Ге́рманович Криви́цкий; birth name Samuel Gershevich Ginsberg, Самуил Гершевич Гинзберг, June 28, 1899 – February 10, 1941)[1][2] was a Soviet military intelligence spymaster who defected to the West and revealed plans for the signing of the Molotov–Ribbentrop Pact.

Walter Krivitsky was born on June 28, 1899, to Jewish parents as Samuel Ginsberg in Podwołoczyska, Galicia, Austria-Hungary (now Pidvolochysk, Ukraine).

Krivitsky operated as an illegal resident spy, with false name and papers, in Germany, Poland, Czechoslovakia, Austria, Italy, and Hungary.

He is credited with having organised industrial sabotage, stealing plans for submarines and planes, intercepting correspondence between Nazi Germany and Imperial Japan, and recruiting many agents, including Magda Lupescu ("Madame Lepescu") and Noel Field.

Following the decision to create the International Brigade in September 1936, Krivitsky organised in The Hague the recruitment of volunteers for the Spanish Civil War.

While he was in the Hague, the General Staff of the Red Army was subjected to the Great Purge in Moscow, which Krivitsky and his close friend, Ignace Reiss, also then stationed abroad, found deeply disturbing.

In Paris, Krivitsky began to write articles and made contact with Lev Sedov, Trotsky's son, and the Trotskyists.

Sedov died mysteriously in February 1938, but Krivitsky eluded attempts to kill or kidnap him in France, partly by fleeing to Hyères.

[6] With the help of journalist Isaac Don Levine and literary agent Paul Wohl, Krivitsky produced an inside account of Stalin's underhanded methods.

Torn between a lingering dedication to Marxist-Leninist ideology and his growing detestation of Stalinism, Krivitsky came to believe that it was his duty to cooperate with the U.S. intelligence community.

It is certain, however, that Lavrenty Beria, the head of the People's Commissariat for Internal Affairs (NKVD), learned of Krivitsky's testimony and ordered operations to assassinate him.

His body was lying in a pool of blood, caused by a single bullet wound to the right temple from a .38 caliber revolver found grasped in Krivitsky's right hand.

[19][20] People with close ties to Krivitsky later recounted opposite interpretations of his death: In the United States, he had to make a new start in life, without knowing the country or the language.

He went to a hotel in Washington, wrote a letter to his wife and one to his friends, and put a bullet through his head... To those who knew his handwriting, his style, his expressions, there could be no doubt that he had written them.

"[12] X., arriving from New York, confidentially assures me that the name of the GPU agent who assassinated Walter Krivitsky in a Washington hotel (winter 1940–1941) is known, as well as all the details of the affair.

[1] Alek died of a brain tumor in his early 30s after he had served in the United States Navy and studied at Columbia University.

Tonia, who changed her surname legally to "Thomas", continued to live and work in New York City until she retired to Ossining, where she died at 94 in 1996 in a nursing home.