I need to know if there is a way that I can tell if one of my admins has accessed read an email from one of our executive's archive account. I've been reading through the "mailbox.log" and I can see that he accessed her archives, but I need to know which message he has opened or read. It doesn't appear that I can link any entry in the mailbox.log file to a particular message.

Is there something I'm missing? Is there a better log file I should check out? Any help would be appreciated as this man's job is at risk.