diff --git a/frigate/events/audio.py b/frigate/events/audio.py
index 4f40334d4..e1d25e018 100644
--- a/frigate/events/audio.py
+++ b/frigate/events/audio.py
@@ -206,7 +206,7 @@ class AudioEventMaintainer(threading.Thread):
                 now - detection.get("last_detection", now)
                 > self.config.audio.max_not_heard
             ):
-                self.detections[detection["label"]] = None
+                del self.detections[detection["label"]]
                 requests.put(
                     f"{FRIGATE_LOCALHOST}/api/events/{detection['id']}/end",
                     json={