By that time, 1939, Bulgaria had become increasingly subservient to German interests and had embarked on an official policy of anti-Semitism. In early 1941 Bulgaria enacted its imitation of the Nazi Nuremberg Laws eliminating the civil rights of its Jewish citizens; and beginning a process leading to property expropriation, internment, and forced labor. Shortly thereafter it became a military ally of Nazi Germany.
During those years Yakova became increasingly involved with young socialist organizations and soon became part of the underground resistance. For many young Jews, idealism combined with Bulgaria’s increasing adherence to Nazi goals furthered a commitment to Zionist and left-wing organizations and often the underground. In its early years, the armed resistance was small and incapable of major actions. Its strategy was to establish small “urban fighting groups” to engage in sabotage and assassination and Yakova was a member of one of the groups taking the nom de guerre “Ivanka”.
These groups, with varying success, sabotaged military warehouses, factories, fuel depots, communications, and railways, but their most significant actions were a string of assassinations in 1943. Included in the victims were German agents, Nazi sympathizers, and informers, but the most prominent victim, assassinated by Yakova, was General Hristo Lukov – a former Minister of War and leader of the fascist organization “The Union of Bulgarian Legionnaires.”
While Bulgaria provided military support to German forces, it had refused to open an Eastern front and attack Russia. Lukov, a friend of Herman Goering, had constantly pressed Tsar Boris III and his government to take a more active military role, particularly against the Russians. As German discontent with Bulgaria’s inaction increased it was widely rumored that the Nazis were going to support a coup d'état and place Lukov in charge. This then raised the curious situation where both the resistance and the Tsar benefitted from Lukov’s removal.
Later in 1943 the partisan movement grew stronger and ended the activity of the urban groups and Yakova joined a partisan detachment in Western Bulgaria. By Spring of 1944 partisan actions prompted the government to assemble a force of about 100,000 in an attempt to crush the partisans. While the overall effect was minimal, Yakova was captured while alone and returning to her unit. Brutally raped, tortured, and mutilated she died on June 18, 1944, shortly after her 21st birthday.