Mendel (Pinter) Rokach was the first gazan of the Israelitic Community of Rotterdam. “He visited several yeshivoth, including that of the well-known Lubliner rav Maier Schapiro. Appointed in Stanislau in 1932, in Lemberg in 1936, in Rotterdam in June 1939.”
Source : D. Hausdorff, Jizkor. Plates atlas of three and a half centuries of the history of the Jewish community in Rotterdam from 1610 to ±1960 (Baarn 1978) page 81
A * photo of him can be found on page 80 of the same book.