How about this?
Find his ip, and find the company he is working for.
Then, don't warn him or anything, just send an email to abuse@his company.com or hr@his company.com or president@his company.com, operations@his company.com (visit his website and get a few such addresses) .. saying, (feel free to reword but the following is a general idea
).
"We would like to report a violation coming from your domain, by a user presumably within your organization. Following are our requests to him to stop doing this .. (attach).
Here is why we feel this originated from within your organization. (attach)
We realize that in order to provide a free working atmosphere to your employees in your esteemed organization, you are required to give them a free hand on internet access, but we would glady appreciate if you could request this user not to tarnish a useful and valuable source of information to the immigrant community. (Rajiv can word this para better)
Once again, any help provided in this regard would be highly appreciated.
Sincerly,
Rajiv Khanna
Attorney at law (do mention this)."
Important, donot warn this user, let the HR department of his company find him and thrash his ass. Morally we wouldn't be responsible, since we did warn him, public opinion would be on our side, since the users don't like him.
That will shut him up for certain.
I know your first reaction would be, Nah lets give him another chance, but take my opinion, he's troubling us, he doesn't get the first chance, leave alone another.
They might not heed to anything, but hey atleast we tried.