I work for a company in which an ex-employee had administrative access to Microsoft Exchange 2007, and I understand that at some points this person had email which was sent to other employees also forwarded on to him.

Upon taking over the administration of the server, of course all of his known accounts were closed, and any of those forwarding rules were removed. However, I would like to ensure that we didn't miss anything.

What would be the best way to ensure that: (1) There isn't still some sort-of email being forwarded on to him somewhere? (2) That he doesn't have some sort-of other access to an inbox or another employee's email?

I am less concerned about access to the box itself as I am that there is an existing email rule somewhere that is still getting run, or that there is a distribution list that we missed, etc.