Joseph Egger was married to Juliette Celina Warradijn. The couple had a daughter, Selma Henriette. The three members of the family were in hiding in Amsterdam, the parents on the Elandsgracht and the daughter on the Tweede Helmersstraat. Following a tip, Selma Henriette was picked up by two members of the Henneicke group. They pressured the ten-year old girl to disclose the address where her parents were hiding. After giving them a false address twice, she succumbed to their threats and told them where her parents were.
A. van Liempt, Kopgeld. Nederlandse premiejagers op zoek naar joden, 1943 (Amsterdam 2002) 220
In addition, a Jokos file (number 8238) on this family is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.The Jokos file reveals that a claim was lodged for compensation for valuables surrendered to the Lippmann-Rosenthal looting bank (L-claim, number 2919/9041).