Black Book

In 1944, Rachel Stein, a Dutch-Jewish singer who had lived in Berlin before the war, is hiding from the Nazi regime in the occupied Netherlands. When the farmhouse where she had been hiding is accidentally destroyed by an American bomber, Rachel manages to escape the area thanks to a local man, Rob, and visits a lawyer named Smaal, who provides her with some of her father's money so that she can flee, helped by a man named Van Gein. Rachel and Rob are reunited with her family and try to flee by boat through the Biesbosch with other Jews from the Nazi-occupied part of the Netherlands to the liberated southern part of the country. However, it turns out to be a trap. They are ambushed on the river by members of the German SS, who kill them and rob the bodies of their cash and other valuables. Rachel alone survives, but she does not manage to escape from occupied territory.
Using a non-Jewish alias, Ellis de Vries, Rachel becomes involved with a Dutch resistance group in the Hague, under the leadership of Gerben Kuipers and working closely with a doctor in the Resistance, Hans Akkermans. Smaal is in touch with this Resistance cell. When Kuipers' son and other members of the Resistance are captured, Ellis agrees to help by seducing local SD commander HauptsturmfÃ¼hrer Ludwig MÃ¼ntze, bleaching all of her hair blonde. MÃ¼ntze invites her to a party at the local SD headquarters, and there, Ellis recognises ObersturmfÃ¼hrer GÃ¼nther Franken, MÃ¼ntze's brutal deputy, as the SS officer who oversaw the massacre of her refugee party. She obtains a job as a secretary at the SD headquarters while also falling in love with MÃ¼ntze, who, in contrast to Franken, is not abusive or sadistic. He realises that her hair is bleached and she is a Jew, but does not care. She also becomes friends with her Dutch colleague Ronnie, who collaborates with the Germans, working for them, being sexually available to them (particularly Franken), and accepting stolen gifts from them.
Thanks to a hidden microphone which Ellis plants in Franken's office, the Resistance realises that it was Van Gein who betrayed Rachel, her family and the other Jews to the SS in return for a cut of the profits. Against Kuipers' orders, Akkermans and others decide to abduct Van Gein to expose the suspected traitor. The plot goes wrong when Akkermans' chloroform fails to work; Van Gein begins to succumb to it, but suddenly fights back and is killed. Franken responds by planning to kill forty hostages, including most of the plotters, but MÃ¼ntze, who realises the war is lost and has been negotiating with the Resistance, cancels the order.
MÃ¼ntze confronts Ellis and demands that she tell him her story, which she does. On her evidence he confronts Franken with a superior officer, ObergruppenfÃ¼hrer KÃ¤utner, who orders Franken to open his safe, in a search for the money, gold and jewels stolen from the Jews he had killed. (Murdering Jews was not against SS regulations, but personally stealing their wealth was a capital offense.) However, the safe reveals nothing, and Franken tells KÃ¤utner that MÃ¼ntze has been negotiating with Dutch resistance "terrorists" for a truce. MÃ¼ntze is condemned to death and imprisoned, along with the members of the resistance cell Franken was already planning to shoot as a reprisal for the killing of Van Gein. Ellis agrees to participate in a rescue attempt for the resistance prisoners only on the condition that they free MÃ¼ntze too and, albeit reluctantly, the others agree. The plan has been betrayed by an unknown insider, and the would-be rescuers find the prisoners' cells to be filled with German troops. Only Akkermans and one other man survive the "rescue".
Ellis is subsequently arrested by Franken and taken to his office, which she had bugged. Franken has known about her and the bug for some time. Knowing that the resistance is listening in, he stages a confrontation to make the resistance group believe Ellis is the Nazi collaborator, responsible for the failure of the rescue operation. Hearing this, Kuipers and his companions swear to hunt her down and make her pay for her treason. Ronnie, having learned of Ellis's role with the Resistance, helps Ellis and MÃ¼ntze escape.
When the country is liberated by the Allies, Franken attempts to escape by boat, but is killed by Akkermans who takes the loot Franken was trying to escape with. Suspecting Smaal is the traitor, MÃ¼ntze and Ellis return to confront him. Smaal denies the accusations. He shows them the titular black book in which he had detailed all his dealings with the Jews he had ostensibly helped. However, both Smaal and his wife are murdered before they can leave the building. Not getting a good look at the killer, MÃ¼ntze chases him into the street, only to be recognized by the triumphant Dutch and arrested by the Canadians. The Dutch also recognize Ellis and arrest her as a "collaborator", but not before she grabs the black book.
MÃ¼ntze is brought before the ranking Canadian forces and finds that they have enlisted the assistance of KÃ¤utner in keeping order among the defeated German forces. KÃ¤utner convinces a Canadian colonel that under military law the defeated German military retains the right to punish its own soldiers. He produces the death warrant he previously issued against MÃ¼ntze for his negotiations with Ellis's resistance cell. Although initially opposing the idea of murdering a witness, the Canadian colonel finally agrees, and MÃ¼ntze is immediately executed by a firing squad of German troops.
Ellis is imprisoned with other accused collaborators, and humiliated and tortured by the violently anti-Nazi volunteer jailers, but is rescued by Akkermans, now a colonel in the Dutch Army. Akkermans brings her to his medical office, and tells her that he killed Franken when the Nazi tried to escape. He shows her the cash and jewels stolen from Franken's Jewish victims. When informed about MÃ¼ntze's fate, Ellis goes into shock, and Akkermans administers a tranquilizer which is in fact an overdose of insulin. Ellis, feeling dizzy, sees the bottle of insulin and survives by quickly eating a bar of chocolate. She realizes then that Akkermans was a traitor who had collaborated with Franken and had killed the Smaals. While Akkermans is distracted, waving to a crowd that cheers him, she jumps from his balcony into the crowd below and runs away. He tries to follow her, but is blocked by the very same people cheering him as a hero of the Resistance.
Ellis proves her innocence to Canadian military intelligence and to the former Resistance leader Gerben Kuipers by means of Smaal's black book, which lists how many Jews (including Ellis's brother) had been taken to Akkermans for medical help just prior to their murders. Together, Ellis and Kuipers intercept the fleeing Akkermans, who is hiding in a coffin in a hearse with the stolen money, gold and jewels. They quickly kill the driver, and while Kuipers drives the hearse, Ellis screws down the coffin's secret air vents. They drive to Hollands Diep where the SS trap had been sprung, and wait until Akkermans suffocates. Ellis and Kuipers are left wondering what to do with the stolen money and jewels.
The scene changes to Israel in 1956, and shows Rachel meeting her husband and their two children, and walking back into Kibbutz Stein, which a sign at the gate announces was funded with the recovered money stolen from Jews killed during the war. The scenes in Israel were produced by Hocus Focus Films, Israel, led by Micha Israel Kovler.

Question: Who betrayed Rachel to the SS?
Answer: Van Gein