I've handled investments by people from all over the world into US companies- typically LLCs through private placements of membership interests. First, do your diligence on the person- require that you see the person's passport, proof of residency, etc., and do a background check, and second, make sure that your purchase agreement contains standard securities law representations-usually that the person is an accredited investor:
http://www.sec.gov/answers/accred.htm I would also make sure that the person can make additional representations, such as "no money laundering", etc.
My company (in US) has bunch of EU investors. Your purchase agreement just need to state your investors certify they comply with their local laws. That is it (from what I remember).
BUT, if this person is in US under Green Card or any kind of visa, that is when it might get trickier.
In either case, you have to have some help from an attorney. Don't be cheap with this. With all the Ponzi schemes going on and bubble underway, regulators are looking for opportunities to make an example out of you.
The investor's share purchase agreement needs to be drafted appropriately.
However, there is no prohibition against an Indian citizen in the U.S. - or anyone else - investing funds merely because they previously were in a tax haven country.
Disclaimer: This information does not constitute legal advice and does not establish an attorney-client relationship.