diff --git a/functions/api/events-team/events/[id].ts b/functions/api/events-team/events/[id].ts
index dc80673..c89f237 100644
--- a/functions/api/events-team/events/[id].ts
+++ b/functions/api/events-team/events/[id].ts
@@ -35,6 +35,12 @@ export async function onRequestDelete(context: RequestContext) {
       403,
     );
 
+  if (typeof eventData.performed_at !== "number")
+    return jsonError(
+      "Event cannot be deleted because it has already been marked as completed or forgotten",
+      400,
+    );
+
   await context.env.D1.prepare("DELETE FROM events WHERE id = ?;")
     .bind(eventId)
     .run();