Stella Ingrid Goldschlag (10 July 1922 – 26 October 1994), also known by her married names Stella Kübler, Stella Kübler-Isaaksohn and Ingrid Gärtner, was a German Jewish woman who collaborated with the Gestapo during World War II, operating around Berlin exposing and denouncing Berlin's underground Jews, after being tortured in Gestapo custody and falsely being promised the safety of her family. After the war, Goldschlag "converted to Christianity and became an open anti-Semite".

The number of people she betrayed or delivered to the Nazis has been estimated at anywhere from 600 to 3,000.

Early life Goldschlag was born on 10 July 1922 in Berlin to a middle-class assimilated German Jewish family. Her father, (1889–1944), was a conductor, composer and journalist, and her mother, (née Lermer; 1890–1944), was a singer. She was raised in Wilmersdorf, Berlin, and was an only child. The Goldschlag family often had economic troubles and sometimes had to rely on welfare as Goldschlag's father struggled to find stable work.

Goldschlag went to elementary school and then attended the Hohenzollern lyceum. After the 1933 seizure of power by the Nazis, she, like other Jewish children, was forbidden to attend a state school by Nazi racial policies, so starting in 1935, she attended the Goldschmidt School in Dahlem, set up by the local Jewish community. At the school, she was known for her beauty and vivacity, but she also stood out because she studied on a scholarship and was not from an affluent family. Goldschlag resented being seen as poor and at times she would even reject her Jewish ancestry by claiming that her mother was a Christian.

The family fell on hard times when the 1933 Law for the Restoration of the Professional Civil Service was used to purge Jews from positions of influence and her father Gerhard lost his job with the newsreel company Gaumont. Her parents attempted to leave Germany after Kristallnacht in 1938 to escape the Nazi regime, but were unable to gain visas for other countries. Goldschlag completed her education in 1938, training as a fashion illustrator at the School of Applied Art in Nürnbergerstraße.

Going underground and collaboration In 1941, Goldschlag married a Jewish musician, Manfred Kübler. They were former bandmates at Goldschmidt and met again when both were working as forced labourers in the Ehrich & Graetz factory in Berlin. In about 1942, when the large deportation programme of Berlin Jews into extermination camps began, she disappeared underground, using forged papers to pass as a non-Jew – often avoiding ID checks altogether. In early March 1943, Goldschlag and her parents, who had also been working as forced labourers by then, were arrested as part of the Fabrikaktion. Goldschlag was taken to Bessemerstrasse women's prison where she was interrogated and tortured; on 10 July 1943 (coincidentally her 21st birthday), she managed to escape briefly during a visit to the dentist, but was quickly rearrested as she sought refuge in her parents' home, which was already being watched by the Gestapo, and she was brutally tortured once more after being recaptured.

On 24 August 1943, the Bessemerstrasse prison was bombed during an air raid, which damaged her cell and allowed her to escape yet again, but this time she went to where her parents were being detained at the detention and assembly camp of Grosse Hamburger Strasse (the site of a Jewish cemetery that was desecrated and destroyed by the Nazis), intending on sharing their fate, but she was taken back to Bessemerstrasse.

In order to avoid the deportation of herself and her parents, she agreed to become a "catcher" () for the Gestapo, hunting down Jews hiding as non-Jews (referred to as "submerged", ). Goldschlag at first gave up names of Jewish fugitives only under torture, which happened for the first time after her failed escape attempt when she was captured with a list of names that included that of a Jewish man named Mikki Hellmann, who had provided her with a forged passport and whom Goldschlag lured into a trap after which he was captured. However, she would later start to collaborate with the Gestapo more willingly.

After collaborating with Hellmann's arrest, Gestapo investigators found out that Goldschlag had also been in contact with a prominent passport forger named Samson Schönhaus, who operated under the alias Günter Rogoff. Schönhaus was involved in an extensive Jewish-Catholic Polish resistance network and had provided at least 40 Jewish prisoners (in the camp in which Goldschlag was kept) with forged food ration cards, passports and various other identity documents. Thus, Gestapo officers were desperately looking for Schönhaus, and, discovering Goldschlag's connection to him, they offered her a more permanent arrangement collaborating with them and delivering Jewish fugitives to them: Schönhaus was able to escape to Switzerland after two of his compatriots were exposed, but Goldschlag's arrangement with the Nazis continued. She was promised that she and her parents would not be deported, plus she would be paid a reward of 300 Reichsmark for each Jew that she betrayed while she operated mostly around Berlin.

Goldschlag proceeded to comb Berlin for such Jews, and, as she was familiar with a large number of Jews she knew from her years at Goldschmidt School, she was very successful at locating her former schoolmates and handing their information over to the Gestapo, while keeping up the façade as a Untergetauchte herself. Some of Goldschlag's efforts to apprehend Jews in hiding included promising them food and accommodation; she would also follow clues provided to her by the Gestapo. She would also monitor funerals of ethnic Germans who were known or suspected to have married Jewish spouses and betray them to the authorities, as pre-war marriages to an "Aryan" allowed some Jews to avoid detection. Estimates of the number of her victims vary, depending on the source, from 600 to 3,000 Jews. Goldschlag's charisma and striking good looks were a great advantage in her pursuit of underground Jews. The Nazis called her "blonde poison", while Jews in hiding knew her as the "Blonde Lorelei". She was also referred to as "the blonde ghost".

The Nazis broke their promise regarding sparing Goldschlag's parents and deported them, initially to the Theresienstadt concentration camp on 23 February 1944. Goldschlag pleaded with her superiors to spare her parents, but to no avail, but was promised to become an honorary Aryan after the war. Her parents were later transported to Auschwitz and murdered. Goldschlag's husband, Manfred, was deported in 1943 to Auschwitz, along with his family. It was the belief of his family that Goldschlag had betrayed even her own husband and in-laws to the Nazis. However, the Kübler family was deported before Goldschlag's collaboration with the Nazis began.

While Goldschlag continued to hunt down Jews, she and her fellow "catchers", numbering around 15 to 20 by this time in Berlin, were targeted for revenge by their potential victims. An organization called the Society for Peace and Reconstruction (Gemeinschaft für Frieden und Aufbau or GFA) was actively planning to kill Goldschlag (and her second husband, Rolf Isaaksohn). A plan to poison her coffee was abandoned, as were plans to have her dentist poison her during an appointment and luring Goldschlag and Isaaksohn to an address by a rumor of Jews in hiding living there.

GFA instead sent Goldschlag a fake death sentence written on official court document paper and informed her that if she was seen on the streets [after the war] by one of their agents she would be killed instantly. Even if the threat was only for intimidation, it was seen as a valid one, and Goldschlag's superior pulled her and the other members of the Search Service from the streets for two weeks and later issued them with pistols for protection.

Goldschlag continued working for the Gestapo until March 1945. During that time, she met Isaaksohn and married him on 29 October 1944. Isaaksohn was a fellow Jewish catcher. Goldschlag was not as active as a catcher during this time as she had been previously due to the fact that she was too well-known to be of effective use and there were not as many Jews left in Berlin due to the Nazi purges and the zealousness of Goldschlag and her compatriotsand those who remained in the city were too well hidden.

In 1933, the Jewish population of Berlin was estimated at 160,000, but by the end of the war, the Jews who had managed to remain hidden numbered somewhere between 1,400 and 1,700.

Goldschlag still continued to scout out addresses where Jews were known to have lived. Her loyalty to the cause was also questioned by her superiors and members of her team after she told her superior Dobberke that she could not find any more Jews and wanted to stop being a catcher. This was dangerous, as it put both her and the other catchers at risk of deportation, and Isaaksohn vehemently denied Goldschlag's claims and told his superiors that they were operating very successfully in tracking down Jews.

Around this time, Goldschlag would also become romantically involved with Heino Meissl, a publicist for a film company and fellow Nazi collaborator.

Final months of World War II In February 1945, Goldschlag found herself pregnant, with the likeliest father being Meissl. While Goldschlag expected him to acknowledge his paternity and take care of her and their unborn child, Meissl instead vanished, leaving Goldschlag to fend for herself.

Goldschlag lost the support of any of her lovers and her Nazi superiors having other more pressing concerns with the advancement of the Western Allies, so in the early stages of the Battle of Berlin in April, Goldschlag went into hiding. The same month, she gave birth to her daughter, Yvonne, in Liebenwalde.

Post-war life She was found by the Soviets in October 1945 and arrested for collaboration. In custody, Goldschlag still claimed to have been victimized during the Holocaust, both as a cover and in order to claim (Opfer des Faschismus; OdF) status. In an attempt to corroborate this, in early 1946, she was accompanied to a Jewish Community office in Berlin to be registered, which would have made her eligible for additional food rations from aid services. Instead, Jewish survivors there recognized her immediately and while an official protected her from being beaten up by an angry mob, the official did allow for her hair to be cut off.

Brought to trial, Goldschlag was found guilty and sentenced to ten years of hard labor in June 1946. Her daughter had been taken from her to protect her from "having to suffer for her mother's sins" and was later placed with foster parents; when they emigrated to the United States, she was placed with another family in Berlin. In an ironic twist of fate, Goldschlag would serve out part of her sentence in Soviet NKVD special camp Nr. 7 (established at the former Sachsenhausen concentration camp) before being transferred to Torgau and Hoheneck fortress. The last part of her sentence was spent at Waldheim Hospital, where Goldschlag was treated for tuberculosis.

Following the completion of her sentence, she moved to West Berlin to find her daughter, who had been living there with a Jewish family, to no success. There she was again tried, convicted, and sentenced to ten years' imprisonment in 1957 for being an accessory in several counts of murder. During this second trial, Goldschlag denied all charges and claimed she was the victim of a Jewish conspiracy against her. Despite being convicted, she did not have to serve the second sentence because of the time already served in the Soviet prison. During the second trial, a psychiatrist diagnosed Goldschlag as a "schizophrenic psychopath".