We got some mailboxes which are shared among users.
Suddenly one of those shared mailboxes got empty. The trash folder of the shared mailbox was also empty.
We are sure that no one has logged into the admin account to delete the mails.

We managed to restore the inbox of the shared one, so no mails are lost.

We are just curious why the inbox can get empty overnight. We read that POP3 might be a reason. Just wondering if there are any others?
Also, are there ways to find out what exactly has happened?

thanks, Patrick