Hartog van Cleef was a son of Barend van Cleef and Sophia Johanna van Geldere. He was born on 13 December 1919 in Amsterdam, was not married and worked as a warehouse clerk. He lived at home with his parents, who lived in the Vrolikstraat, from 1928 at number 299 and from 1936 at number 94. Hartog had two sisters, Rozet and Sientje and another little brother Saul. His sister Sientje died at the age of 11 on 1 March 1938, but his brother Saul was only 2 years old and died on 4 October 1924.
After the outbreak of the Second World War, all Jews were obliged to register with the local Population Registers from 10 January 1941. A registration card was made for every Jewish person, but from Hartog's parents, Barend van Cleef and Sophia Johanna van Geldere, there appear to be no registration cards in the file cabinet of the Jewish Council, but from Hartog and his sister Rozet.
This shows that Hartog, probably from the spring of 1942, had to work as a forced laborer in one of the Jewish labor camps. Around 21 or 22 August he was sent from that labor camp to Westerbork from where he was deported to Auschwitz on 24 August 1942 with 518 others. On arrival there he was again put to work as a forced laborer, but it is not known where he had to work under harsh and bad conditions. Nor is his exact date of death known.
That is why the Dutch authorities determined after the war – partly on the basis of survivors' testimonies and other information – that Hartog van Cleef could no longer be alive after 30 September 1942. The Ministry of Justice subsequently commissioned the Municipality of Amsterdam to draw up a death certificate for Hartog van Cleef, in which it was established that he died on 30 September in Auschwitz.
Sources include the Amsterdam City Archives, family card Barend van Cleef, archive cards Barend van Cleef and Hartog van Cleef, the file cabinet of the Jewish Council, registration card of Hartog van Cleef; website Jodentransporten uit Nederland.nl and the death certificate for Hartog van Cleef, drawn up in Amsterdam on 18 August 1950, no. 378 from the A-register 46,folio 65.