This feature is exclusive to the Enterprise and Gold versions of Rocket.Chat. The auditing panel allows specific users to read any conversation between any users. The time range can be chosen freely. An auditing log feature is also available, allowing specific users to verify who run the audit and when a conversation was inspected.
The Audit Panel and the Audit Log are available in the Administration UI.
You can restrict the access to both features to specific roles (for example, to Admin role) using the permissions screen. Also, there are two roles, Auditor and Auditor Log that you can assign to people who should be able to perform the message inspection.
The Auditing Panel allows searching for a specific message, as well as looking through all the messages within the specified period of time, in public channels, private rooms and direct messages.
The auditor does not have to be a participant in the room to be able to read the messages in it. The auditor will not be able to read encrypted messages of other users if he is not a part of the conversation.
You can also check who and when ran the auditing if you have permissions to Audit Log or the respective role.