[Bungleau]

When you get those emails, they're almost never from who they claim to be. If you right-click on the email in your email client and look through the options or properties (depending on program), you should see some header information, including the fields (which is usually the spoofed address) and (among others), which will give you a better clue of who the real sender was.

I used this technique to track down someone in one of my wife's groups who was infected with something and constantly sending out emails. When the same name appears over and over again, you may have found the culprit