Levie Hakker was a son of Jonas Hakker and Sara Kok. He married Betje Velleman in Amsterdam on 11 June 1884, a daughter of Zacharias Velleman and Roosje David Gans. Levie and Betje had ten children together: ons son has died in infancy, three children have survived the Holocaust but the others, Sara, Zacharias, Rosette, Clara, Benjamin and Anna have been killed in the Shoah. Also Levie and his wife Betje have been killed both on 21 May 1943 in Sobibor.
City Archive of Amsterdam, family registration card of Levie Hakker, website www.wiewaswie.nl, the file cabinet of the Jewish Council of Amsterdam, records Levie Hakker and Betje Velleman and an addition of a visitor of the website.