Jozef Israël was married to Henderika Israël-van Gelder, daughter of Betje van Gelder-Abrahams. The couple lived at 75a Johan Willem Frisostraat in Groningen. When they were fetched, several items of jewelry and a few valuables were taken from them. A child of the couple survived the war.
The archive of the Stichting Sieraden-Comité contains correspondence, a statement taken under oath, a list of stolen items of jewelry and a statement of the right to inheritance.
NIOD, Records Stichting Sieraden-Comité, box HF 11, file 158
In addition, a Jokos file (number 9197) on this family is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.