A search for “Rosenberg” in the Open Public Access system of the National Archives brings up a strange and poignant collection of documents: a passport picture of a family with the mother clutching a tiny infant, childlike sketches of shapes, a smiling couple, and an empty Jell-O box.
In September 1949, the White House announced the Soviets had successfully detonated an atomic bomb. The secrets behind the construction of Fat Man and Little Boy—the atomic bombs that had devasted Nagasaki and Hiroshima—were in the hands of the Soviets.
In 1950 the FBI arrested Emil Julius Klaus Fuchs, a German-born British atomic scientist. Although Fuchs did not know his American contact, the FBI eventually identified Harry Gold, a Philadelphia chemist. And in turn, this led to David Greenglass, a U.S. Army soldier and Soviet agent who had been assigned to Los Alamos, NM, where the bombs were built.
In June 1945, Greenglass had given material in to Anatoli Yakovlev, former Soviet vice-consul in New York City. And according to the FBI, Julius and Ethel Rosenbergs had been instrumental in persuading and assisting David Greenglass, brother of Ethel Rosenberg, in passing the secrets to Yakovlev.
But what about the Jell-O box?
Like a “Best Friends” necklace, pieces of the Jell-O box could be matched, and the spies would be able to confirm their identities.
The Greenglasses were living in Albuquerque when a man came to their home, introduced himself saying “Julius sent me,” and produced a piece of Jell-O box. It matched the one David Greenglass was holding. The other spy was chemist Harry Gold.
A Jell-O box was introduced at the trial. It was not the original box, but “trial transcript shows that the prosecution introduced this facsimile Jell-O box to represent the recognition signal.” The evidence is now part of the holdings of the National Archives at New York City.
The Rosenbergs denied all espionage allegations, but on April 5, 1951, the couple received a sentence of death, and both were executed on June 19, 1953.