Valid visitor visa to USA

Connected with a Russian lady on the internet. She asked me to help her to obtain passport and visa. In return, I asked her to show me the passport and tourist visa she would obtain. Her Russian passport was issued in October and her visa was issued before Christmas. She complied and sent me copies of documents. How can I tell if these documents are indeed real? Then, she kept asking for more money for tickets and fees for customs, etc. She will not give me her address or phone number, just a email address. Are these signs of frauds? Where can I seek help to look into the documents and investigate this matter before I sink too deep?

Then, she kept asking for more money for tickets and fees for customs, etc. She will not give me her address or phone number,

It's a scam, just from that line alone.

If you can forward the email you received with the passport and visa to one of the Mods in here, Green tags, I am sure one of them will be able to post for you, or failing that forward to me at my email and I will post them

This sounds like a common standard Russian Romance Scam, Do Not Send any money.

Take care