Malvina Gruber, née Hofstadterova (born 6 December 1900 in Jamborkretz, Czechoslovakia) was a Jewish[1] Comintern agent, who was part of a Soviet intelligence network in Belgium and France, that was later called the Red Orchestra ("Rote Kapelle") by the Abwehr, during Nazi regime.

From 1938 to 1942, Gruber worked as assistant to Soviet agent Abraham Rajchmann, a forger, who provided identity papers, e.g. the Kennkarte, Carte d'identité and travel permits, for the espionage group.

[2] In July 1941, Gruber escorted Soviet agent and secret writing specialist Anton Danilov from France to Belgium where he became part of the espionage network run by Anatoly Gurevich.

[7][8] Rajchmann also decided to cooperate with the Abwehr resulting in his betrayal of his mistress, who was arrested in Paris on the 12 October 1942 at the Cafe de la Paix.

[10] Together with Rajchmann, she enthusiastically collaborated in betraying several agents in the network both in Brussels and later in Paris, that surprised German officials.

[11] She admitted the existence of a Soviet agent Anatoly Gurevich and his probable location, as well as exposing several members of the Trepper espionage network in France.