diff --git a/src/debugger.cc b/src/debugger.cc
index 0b76e8a..7dfbd22 100644
--- a/src/debugger.cc
+++ b/src/debugger.cc
@@ -1633,6 +1633,7 @@
   UniquePtr<Context> context(Context::Create());
   Thread* thread = DecodeThread(thread_id);
   if (thread == NULL) {
+    *result = 0;
     return JDWP::ERR_INVALID_THREAD;
   }
   GetThisVisitor visitor(thread->GetManagedStack(), thread->GetTraceStack(), context.get(), frame_id);