There is a deathcertificate of Jacob Karel Danneboom in the archives of the city of Zwolle that states that his date of death is 20 January 1944.
Information from the 'Cartotheek of the Jewish Council' and 'Herinneringscentrum Westerbork' shows that Jacob Karel Danneboom arrived at Westerbork on 13 July 1944 and that he is deported on 3 September 1944 to Auschwitz.
Source: Cartotheek van de Joods…