diff --git a/core/Controllers/GroupController.php b/core/Controllers/GroupController.php
index b95013e72f330bfe371a83916b7985d2bc3d7a80..14e2391aee2bf53b7214b596a04516e029d7c97e 100644
--- a/core/Controllers/GroupController.php
+++ b/core/Controllers/GroupController.php
@@ -111,7 +111,7 @@ class GroupController
             return $response->withStatus(400)->withJson(['errors' => 'Group not found']);
         }
 
-        $group['users']     = GroupModel::getUsersByGroupId(['groupId' => $group['group_id'], 'select' => ['users.user_id', 'users.firstname', 'users.lastname']]);
+        $group['users']     = GroupModel::getUsersByGroupId(['groupId' => $group['group_id'], 'select' => ['users.id', 'users.user_id', 'users.firstname', 'users.lastname']]);
         $group['security']  = GroupModel::getSecurityByGroupId(['groupId' => $group['group_id']]);
         $group['services']  = GroupModel::getAllServicesByGroupId(['groupId' => $group['group_id']]);