diff --git a/lib/twitter.py b/lib/twitter.py
index 1de464d..a9d1d8c 100644
--- a/lib/twitter.py
+++ b/lib/twitter.py
@@ -126,7 +126,7 @@ def refresh_posts(posts):
     for post in posts:
         tweet = next((tweet for tweet in tweets if tweet['id_str'] == post.twitter_id), None)
         if not tweet:
-            session.delete(post)
+            db.session.delete(post)
         else:
             post = db.session.merge(post_from_api_tweet_object(tweet))
             refreshed_posts.append(post)