The two are inextricably intertwined. Only the sender or recipient can provide lawful access to an end-to-end encrypted message. That's the whole point of end

The two are inextricably intertwined. Only the sender or recipient can provide lawful access to an end-to-end encrypted message. That's the whole point of end-to-end encryption. e.g. an informant can take screenshots or copy the message text or a defendant can be compelled to provide their fingerprint by subpoena.