diff --git a/scripts/deregister-room.ts b/scripts/deregister-room.ts
index 1e875c1..ed77921 100644
--- a/scripts/deregister-room.ts
+++ b/scripts/deregister-room.ts
@@ -163,7 +163,6 @@ const scheduledTaskIds = (
 ).map((r) => r.id);
 const qS = scheduledTaskIds.map(() => '?').join(',');
 const safeFolderList = [...safeFolders];
-const qF = safeFolderList.map(() => '?').join(',');
 
 const count = (t: string, where: string, a: unknown[]): number =>
   (
@@ -221,15 +220,22 @@ for (const t of [
   addJid(t);
 }
 // sessions are keyed by group folder — only purge folders not shared with a
-// surviving room.
-if (safeFolderList.length) {
+// surviving room. Reviewer/arbiter sessions are stored under the colon-suffixed
+// group_folder (e.g. "<folder>:reviewer"), so include those variants too.
+const sessionFolderKeys = safeFolderList.flatMap((f) => [
+  f,
+  `${f}:reviewer`,
+  `${f}:arbiter`,
+]);
+if (sessionFolderKeys.length) {
+  const qSess = sessionFolderKeys.map(() => '?').join(',');
   plan.push({
     table: 'sessions',
-    n: count('sessions', `group_folder IN (${qF})`, safeFolderList),
+    n: count('sessions', `group_folder IN (${qSess})`, sessionFolderKeys),
     run: () =>
       db
-        .query(`DELETE FROM sessions WHERE group_folder IN (${qF})`)
-        .run(...safeFolderList),
+        .query(`DELETE FROM sessions WHERE group_folder IN (${qSess})`)
+        .run(...sessionFolderKeys),
   });
 }
 
@@ -250,11 +256,17 @@ if (routerPrune) console.log(`  router_state.last_agent_seq: ${routerPrune}`);
 // disk targets
 const diskDirs: string[] = [];
 for (const folder of safeFolders) {
+  // Tribunal rooms keep separate reviewer/arbiter runtime dirs suffixed with
+  // the role (e.g. data/sessions/<folder>-reviewer). Include those variants so
+  // deregistration leaves no leftovers.
+  const folderVariants = [folder, `${folder}-reviewer`, `${folder}-arbiter`];
   for (const d of [
     path.join(GROUPS_DIR, folder),
-    path.join(DATA_DIR, 'workspaces', folder),
-    path.join(DATA_DIR, 'sessions', folder),
-    path.join(DATA_DIR, 'ipc', folder),
+    ...folderVariants.flatMap((f) => [
+      path.join(DATA_DIR, 'workspaces', f),
+      path.join(DATA_DIR, 'sessions', f),
+      path.join(DATA_DIR, 'ipc', f),
+    ]),
   ]) {
     if (fs.existsSync(d)) diskDirs.push(d);
   }