Email Monitoring Software

[Matthew Schwartz]

Hello,

I am looking for some decent free/open source email monitoring software or
solution.  I run Postfix for my SMTP server and Cyrus for POP and IMAP.  A
need has arisen to monitor our email due to a previous abuse of terms by an
employee.  I have attempted to google the issue on two separate occasions
and have come up dry.  I have even investigated creating a mailbox called
archive and a rule that sends all mail to it.  Not an elegant solution, I
know.  However, I am out of ideas.

Thanks,
Matt