In pursuit of Plan A, members of the group were infiltrated into water and sewage plants in several cities, while Kovner went to Palestine in search of a suitable poison.[14] Kovner discussed Nakam with Yishuv leaders, though it is not clear how much he told them and he doesn't seem to have received much support.[17] According to Kovner's own account, Chaim Weizmann approved when he pitched Plan B and put him in touch with the scientist Ernst Bergmann, who gave the job of preparing poison to Ephraim Katzir (later president of Israel) and his brother Aharon.