Earlier, a Holocaust survivors group called on the German auction house Felzmann to cancel Monday’s sale of hundreds of Holocaust artefacts, including letters written by prisoners and other documents that identify many people by name.

A listing of information about the auction on the Auktionhaus Felzmann website on Sunday morning was no longer on the site by midafternoon. The auction house did not immediately respond to calls, an email and a text message on Sunday.

The collection of more than 600 lots at auction in western Neuss, near Düsseldorf, included letters written by prisoners from German concentration camps to loved ones at home, Gestapo index cards and other perpetrator documents, the German news agency dpa reported. The auction was titled “The System of Terror”.

“For victims of Nazi persecution and Holocaust survivors, this auction is a cynical and shameless undertaking that leaves them outraged and speechless,” Christoph Heubner, an executive vice-president of The International Auschwitz Committee, a Berlin-based group of survivors, said in a statement on Saturday.