diff --git a/utils/tracers/ndn-app-delay-tracer.cc b/utils/tracers/ndn-app-delay-tracer.cc
index c0f881d..6eeeeb9 100644
--- a/utils/tracers/ndn-app-delay-tracer.cc
+++ b/utils/tracers/ndn-app-delay-tracer.cc
@@ -53,6 +53,12 @@
 }
 
 void
+AppDelayTracer::Destroy ()
+{
+  g_tracers.clear ();
+}
+
+void
 AppDelayTracer::InstallAll (const std::string &file)
 {
   using namespace boost;