Esther Posener was the widow of Heiman Liefman Spier (1868-1926). Next to Levi Abraham and Jacob, she had four other children. Jeanette and Johanna were her daughters, two other children probably survived the war.
Addition of a visitor of the website
In addition, a Jokos file (number 33815) on this person is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.