diff --git a/backend/forum.py b/backend/forum.py
index 92dd41c..672b686 100644
--- a/backend/forum.py
+++ b/backend/forum.py
@@ -85,6 +85,9 @@ async def get_thread(thread_id: int):
         if post.thread_id == thread_id:
             result.append(post)
 
+    if len(result) == 0:
+        return {'error': 'could not find parent thread'}
+
     return result