diff --git a/anatomy/views.py b/anatomy/views.py
index 70488ea7..0fad88e0 100644
--- a/anatomy/views.py
+++ b/anatomy/views.py
@@ -294,6 +294,10 @@ def loadJsonAnswer(answer):
 def mark(request, pk, sk):
     exam = get_object_or_404(Exam, pk=pk)
 
+    if not exam.exam_mode:
+        raise Http404("Packet not in exam mode")
+
+
     questions = exam.exam_questions.all()
 
     n = sk