Hi George,
I may be able to help you if I knew more about the case. (Feel free to contact me off board if you wish.)
One way to find an email address is use a process called "Internet Profiling". This involves searching the web for your subject. There are lots of places to look. Newsgroups can turn up info as well. To do this, you really need to know some details about the subject, and have an idea of his interests. As an example, if he is into old cars or something as a hobby, you could check out all the locat car clubs and other related sites.
Keep in mind that not everyone uses email and your subject may not have an address. Also, a lot of people use yahoo and hotmail addresses. (The "free" ones) These are hard to break because more of the time, the subject will use false info when the create the email account. I have never found accurate info from one of these types of accounts.
If you do locate a valid address, your best bet is to continue the search and try and track his use of it.
Are you wanting to locate the subject, or are you wanting to just verify the email address, or just see if he has one? Most people today have more than one email address, so keep that in mind also.
I hope this helps...
Wayne Miles
Atlas Information Research
wayne@AtlasResearchUSA.com(863) 604-9982