Whether what you want can be done or not "through channels" depends almost entirely on the reason for the inquiry and the policies of the ISP or other provider where the emailer sends mail. Usually, absent something bad enough to generate a search warrant, you won't get anywhere.
Here are some other ideas:
1. Your party might be able to do a reverse email-to-name search, and if that is successful, work from the name for the address on one of the "people locators" or national white pages.
2. Sometimes, searching newsgroups for the email address will locate posts made by the individual which could have clues - a name, an employer, etc.
3. Just search on the email address itself on Google or Dogpile and see what shows up.
4. If the party has a website, do a "whois" lookup on the domain name.
5. Reach out and touch the perp with an offer he can't refuse. For instance, have your client purchase one of the inexpensive digital cameras available for $20-30 and send a "prize" message to the perp: "Where can we mail your digital camera - absolutely free, no strings, no kidding! - Just give us your opinion of the camera in 30 days, and it's yours to keep forever, no charge, for helping us with our marketing - and we pay the postage, too."
You throw in the last part about the "opinion" because no one gives away something for nothing and the perp will know that - this submerges his suspicions, if any, because he does have to do something for the camera, but it's nearly nothing so he'll probably bite. If not, your client has a camera.
Naturally, your client mails this from a phony hotmail or other site.
Community Safety Services
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