 According to "Toronto Sun" columnist Mark Bonokoski, Zündel's mother was Gertrude Mayer, the daughter of Isadore and Nagal Mayer.Isadore Mayer was a trade union organiser for the garment industry in the Bavarian city of Augsburg.According to Bonokoski, Ernst's ex-wife, Irene Zündel, claimed that the possibility of being at least partly Jewish bothered Zündel so much that he returned to Germany in the 1960s in search of his family's "Ariernachweis", a Third Reich certificate of pure Aryan blood, but was unable to find any such document for his family.