Ok guys long story....
On Friday me and my husband discoverd ( by accident) that all his gmails we being automatically forwarded to a third party but this third party isn't anyone it's his ex wife!!! My husband is pretty good with computers but has never seen this and obviously never set it up! He turned white and immediately changed the setting. We have had a very disturbing weekend thinking of all the information she's had acsess to. So we have spent a lot of time trying to discover how and WHEN this happened. It turns out Gmail does not have a settings history only log in history so we are unaware to how long this has been going on.
Aside from this our business email ( we have an academy) is LINKED to the email so there is a lot of bank and student information. So google ' forum' couldn't help and so we thought we would try here ...
This isa conflicted relationship and we are stressing anyone a whizz out there?
Basically  email has been tampered with SOMEBODY ( obviously his ex) that all his emails have been forwarded to her email address along with all the academy's emails
So we need to find who and when the setting were changed
A lot of settings NOT where or when someone has logged in to  but we need settings history
HELPdoes your Academy not have an IT department?

Gmail doesn't record when settings are modified, not that the GENERAL public can see anyway.
your Server would have a log of user account LOGINS (who/when/where) that may help you narrow things down.How did the Ex get into the house to set all emails forwarded ? ?

If you have a history of the emails you have a history of what she allegedly has posession of...

As far as knowing dates and such personally i would expect worst case scenario...

PS...not to badger but i woulda noticed if my email app was forwarding a looong time ago.

It's in the header/footer of every email you send.A to-do list for you:
1. Get new e-mails accounts.
2. LEARN more about how e-mail works.
3. Talk to an Attorney.