latter successfully, and a Polish Romani woman, Stefania Ciuron, arrived on 12 February 1943 and escaped in April. Josef Mengele, the Holocaust's most infamous physician, worked in the gypsy family camp from 30 May 1943 when he began his work in Auschwitz. The Auschwitz registry (Hauptbücher) shows that 20,946 Roma were registered prisoners, and another 3,000 are thought to have entered unregistered. On 22 March 1943, one transport of 1,700 Polish Sinti and Roma was gassed on arrival because of illness, as was a second group of 1,035 on 25 May 1943. The SS tried to liquidate the camp on 16 May 1944, but the Roma fought them, armed with knives and iron pipes, and the SS retreated. Shortly after this, the SS removed nearly 2,908 from the family camp to work, and on 2 August 1944 gassed the other 2,897. Ten thousand remain unaccounted for. Theresienstadt family camp The SS deported around 18,000 Jews to Auschwitz from the Theresienstadt ghetto in Terezin, Czechoslovakia, beginning on 8 September 1943 with a transport of 2,293 male and 2,713 female prisoners. Placed in sector BIIb as a "family camp", they were allowed to keep their belongings, wear their own clothes, and write letters to family; they did not have their hair shaved and were not subjected to selection. Correspondence between Adolf Eichmann's office and the International Red Cross suggests that the Germans set up the camp to cast doubt on reports, in time for a planned Red Cross visit to Auschwitz, that mass murder was taking place there. The women and girls were placed in odd-numbered barracks and the men and boys in even-numbered. An infirmary was set up in barracks 30 and 32, and barracks 31 became a school and kindergarten. The somewhat better living conditions were nevertheless inadequate; 1,000 members of the family camp were dead within six months. Two other groups of 2,491 and 2,473 Jews arrived from Theresienstadt in the family camp on 16 and 20 December 1943. On 8 March 1944, 3,791 of the prisoners (men, women and children) were sent to the gas chambers; the men were taken to crematorium III and the women later to crematorium II. Some of the group were reported to have sung Hatikvah and the Czech national anthem on the way. Before they were murdered, they had been asked to write postcards to relatives, postdated to 25–27 March. Several twins were