Benjamin Hakker was a son of Levie Hakker and Betje Velleman. He married Jeannette Arpels in Amsterdam on 24 July 1929, a daughter of Salomon Arpels and Sara Kool. The couple had two sons: Louis (nickname Loekie and/or Lex) and Sonny. The complete family has been killed in Sobibor on 9 July 1943.
City Archive of Amsterdam, archive cards of Benjamin Hakker, Jeannette Arpels and website www.wiewaswie.nl