diff --git a/jira/client.py b/jira/client.py
index 8e0f30d63..4adbedbe0 100644
--- a/jira/client.py
+++ b/jira/client.py
@@ -1211,11 +1211,14 @@ def group_members(self, group):
 
         result = {}
         for user in r["users"]["items"]:
-            result[user["key"]] = {
-                "name": user["name"],
-                "fullname": user["displayName"],
+            result[user["id"]] = {
+                "name": user.get("name"),
+                "id": user.get("id"),
+                "accountId": user.get("accountId"),
+                "fullname": user.get("displayName"),
                 "email": user.get("emailAddress", "hidden"),
-                "active": user["active"],
+                "active": user.get("active"),
+                "timezone": user.get("timezone"),
             }
         return OrderedDict(sorted(result.items(), key=lambda t: t[0]))