If the owners/admins of a self-hosted Discourse are asked to cooperate with an investigation by LEOs and provide copies of personal messages between particular users, is there a guide anywhere on how to do this?
Also, if the private conversation is originally between users A and B, but user B decides not to be part of it and leaves the conversation, will the message(s) still be found in searches for messages where both A and B are participants? Is it possible to identify such messages without producing all messages from A?
I understand the issue and yes, some SQL work will do the job.
Looking for action_code = 'user_left' in the posts table contains the corresponding topic_id. Data explorer is convenient because it automatically creates links to profiles and topics or posts in the results: