A new analysis of TM Signal’s source code appears to show that the app sends users’ message logs in plaintext. At least one top Trump administration official used the app.

The clone, TeleMessage, was the subject of a reported hack in which the contents of some direct messages and group chats were stolen.

Smarsh, the Oregon-based owner of TeleMessage, said Monday it was “investigating a potential security incident” and suspended its services out of an abundance of caution.