diff --git a/synapse/rest/admin.py b/synapse/rest/admin.py
index 97eb1954e0..ed9b484623 100644
--- a/synapse/rest/admin.py
+++ b/synapse/rest/admin.py
@@ -38,7 +38,7 @@ class WhoisRestServlet(RestServlet):
         if not target_user.is_mine:
             raise SynapseError(400, "Can only whois a local user")
 
-        ret = yield self.handlers.admin_handler.get_whois(auth_user)
+        ret = yield self.handlers.admin_handler.get_whois(target_user)
 
         defer.returnValue((200, ret))