diff --git a/app/controllers/graders_controller.rb b/app/controllers/graders_controller.rb
--- a/app/controllers/graders_controller.rb
+++ b/app/controllers/graders_controller.rb
@@ -61,4 +61,22 @@
     @submission = Submission.find(params[:id])
   end
 
+  # various grader controls
+
+  def stop 
+    grader_proc = GraderProcess.find(params[:id])
+    stop_grader(grader_proc.pid)
+    redirect_to :action => 'list'
+  end
+
+
+  protected
+
+  def stop_grader(pid)
+    if GraderProcess.grader_control_enabled?
+      cmd = "#{GRADER_SCRIPT_DIR}/grader stop #{pid}"
+      system(cmd)
+    end
+  end
+
 end