Julius and Ethel Rosenberg were charged with the crime of conspiracy to commit espionage, and tried under the Espionage Act of 1917.

The Cast of Characters, in order of appearance:

Igor Gouzenko, Soviet defector

Alan Nunn May, British scientist and spy

Robert Lamphere, FBI agent

Klaus Fuchs, British scientist and spy

James Skardon, MI5 agent

Harry Gold, "Raymond"

Elizabeth Bentley, the "Red Spy Queen"

Anatoli Yakovlev, NKVD agent

David Greenglass, Ethel Rosenberg’s brother

Ruth Greenglass, David’s wife

Julius Rosenberg

Ethel Greenglass Rosenberg

The trail leading up to their arrests is a complex web of espionage, defection, code-breaking, and confession. It is at the same time both thrilling and mundane, a drama of expert sleuthing and puzzling happenstance.

While the trail is not a straight line, a reasonable starting point is Canada, 1945. Igor Gouzenko, a code clerk attached to the Soviet embassy was about to be recalled to Russia. He defected to Canadian authorities, taking with him documents from the Soviet Embassy files. Shortly after Gouzenko's defection, British physicist Alan Nunn May confessed to using his position on the National Research Council of Canada to gather information for the Soviets.

Then came the discovery of a partially burned KGB (formerly NKVD) code book in Finland. With this code book and a set of documents stolen from the New York offices of a KGB-front organization, the FBI, under the direction of Robert Lamphere, began to break the KGB code. One document decoded was a report on the progress of the Manhatten Project, the American effort to build an atomic bomb. The report had been written by Klaus Fuchs, a naturalized British physicist attached to the research group at Los Alamos. After several years, the decoding was finally completed in the summer of 1949.

The question that Lamphere and his colleagues had to ask was: Could Fuchs himself have been a spy while working at Los Alamos, or had Lamphere decoded a report written by Fuchs but obtained by a Soviet agent?

Both the American FBI and the British MI5 began to investigate Fuchs. Although the British had known for years that Fuchs had been a member of the German Communist Party in his youth (the 1930s) before emigrating to England, they had considered him more anti-fascist and anti-Nazi than communist, and had vouched for his reliability to the American authorities when the British team joined the American scientists at Los Alamos. Now, with the decoded report, his prior background became significant. Also, Fuchs' name and address appeared in the Canadian documents taken by Gouzbenko and those connected to the Alan Nunn May affair. Finally, another decoded Soviet message made vague reference to a British atomic spy whose sister attended an American college and lived in the Boston area.

Klaus Fuchs (Rhodes)

Because the FBI did not want the Soviets to know that they had broken the KGB code, interrogators of Fuchs could not reveal their source. Further, they did not want the breaking of the code to be revealed in any court cases that might arise out of the decoding. Unbeknownst to the FBI, Russia knew of Lamphere's success, because he had shared the information with a British Embassy official, Kim Philby. Philby was later discovered to be a Russian spy.

Fuchs, now at the British atomic energy research site at Harwell, England, was confronted by James Skardon of the British MI5, the noted spy-catcher. With gentle urging, not revealing the source of his information, Skardon induced Fuchs to confess.

In his confession, Fuchs recounted the atomic bomb information that he had delivered to the Soviets. He also told Skardon that he had a courier, known to him only as "Raymond." With a physical description of Raymond given by Fuchs and verified by Fuchs' sister and her husband, whom Raymond had visited in Cambridge seeking contact with Fuchs, the FBI narrowed their search to Jewish chemists with specific physical characteristics. Checking their files, the FBI were fortunate to produce three candidates. One of these could not have met Fuchs in New Mexico in 1945. The two others had surfaced before in 1947 before a federal grand jury. They had been named by Elizabeth Bentley, the "Red Spy Queen," who had become an informer after the death of her lover and espionage control. In 1947, neither of the two were indicted. One of these two men was Harry Gold.

Harry Gold (UPI/Bettmann)

Gold named his Soviet contact as "John," in reality an NKVD agent, by the name of Anatoli Yakovlev, stationed in New York, but by 1950, returned to Russia. Yakovlev had instructed Gold not only to deliver documents from Fuchs to him, but to pick up documents in Albuquerque from an American soldier working at Los Alamos on the Manhatten Project. Gold vaguely identified the area where the soldier lived, gave a physical description of him, and recalled that the soldier's wife's name was "Ruth."

The FBI quickly identified the Los Alamos soldier as David Greenglass. In his first interview with the FBI, Greenglass implicated his wife, Ruth, and his brother-in-law, Julius Rosenberg who was married to his sister, Ethel.

On July 17, 1950, Julius Rosenberg was arrested. Three weeks later, on August 11, 1950, Ethel Rosenberg was arrested. Both were held on $100,000 bonds, which neither of them could post. They were incarcerated in the New York House of Detention. As we shall see, they were found guilty of conspiracy to commit espionage on March 29, 1951, and sentenced to death on April 5, 1951.

David and Ruth Greenglass (Rhodes)