diff --git a/bob/bio/face/preprocessor/FaceCrop.py b/bob/bio/face/preprocessor/FaceCrop.py
index 7188bcb92e9eccb9b51e8d8ea853fa2968c181ab..8a4178861658156e1a579db4e4daa673ae5f69a8 100644
--- a/bob/bio/face/preprocessor/FaceCrop.py
+++ b/bob/bio/face/preprocessor/FaceCrop.py
@@ -273,8 +273,9 @@ class FaceCrop (Base):
     if not self.is_annotations_valid(annotations) and \
        not self.fixed_positions and \
        self.annotator is None:
-      logger.warn("Cannot crop face without annotations or fixed_positions "
-                  "or an annotator. Returning None.")
+      logger.warn("Cannot crop face without valid annotations or "
+                  "fixed_positions or an annotator. Returning None. "
+                  "The annotations were: {}".format(annotations))
       return None
 
     # convert to the desired color channel