Siegbert Leo Adler arrived in the Netherlands as a German refugee on 15 December 1938. He was taken in at the Jonggezellenhuis at 13 Jonckbloetlaan in Eindhoven, an assembly point for Palestine Pioneers. On 29 November he found a place to stay at the youth aliyah home at the Hof van Moerkerken in Mijnsheerenland. After this home was closed on 16 October 1940, he and several other wards moved to the youth aliyah home in Loosdrecht, the Paviljoen Loosdrechtse Rade.
On 7 December 1942 Siegbert Leo Adler went into hiding. He left his hiding place to try to escape to Switzerland together with seven other Palestine Pioneers (Bernard Aschheim, Robert Jozef Dürheim, Juda Pinkhof, Lilli Kellner, Fabian Schön, Jossel Waldmann and Esra Jurovics). They were caught at the Belgian border.
F. van der Straaten, Om nooit te vergeten. Herinneringen en belevenissen aan/van Palestina-Pioniers gedurende de oorlogsjaren 1939-1945 (Mijnsheerenland s.a.) 71, 78, 211
This person is commemorated on a memorial in Loosdrecht. More information on this memorial can be found (in Dutch) on the website of the Nationaal Comité 4 en 5 mei.
More information about this person can be found on www.dokin.nl