How Can I Find Out Where an Email Really Came From? here is the answer !

just because an email shows up in your inbox labeled Bill.Smith[at]somehost.com, doesn’t mean that Bill actually had anything to do with it. Read on as we explore how to dig in and see where a suspicious email actually came from.

http://www.howtogeek.com/169539/how-can-i-find-out-where-an-email-really-came-from/

You can see that same information in Windows Mail, Outlook, or even Outlook Express without having to forward the mail to gmail or anywhere else.