GPA sale

Hello Experts,

I have come across a plot property for sale, as the owner of the property is in USA, he has given GPA (to his cousin in India)  which is not registered but validated. Is it safe to buy the same?

What more messure can be taken to be safe.

Also let me know if there are any good lawyer (in HYDERABAD,AP) who can verify the documents and provide opinion/help further documentation & registeration process.

Thanks