In the OP the poster wrote 
Quote
But my friend uses bitcoin and bitcoin is illegal in our country.
That, in a nutshell is the crux of his problem. Despite the fact that you and him know that is illegal in your country you still chose to use BTC and are now bemoaning the predictable results of your illegal activity? I'm amazed people still ignore this and go and give advice on how to use p2p and avoid getting scammed, like that was the only problem!
You could avoid scammers, you could trade with an old account with a lot of good feedback just to realize that it was a honeypot operation and you were selling bitcoin to an undercover agent, and all those that left feedback can't erase it anymore cause they are sitting in jail awaiting trail!!!
Forget the scam, he used something deemed illegal by some moronic govern and he did with the help of a stranger, that's the real problem in this!
Use decentral exchanges (DEX) like bisq.network and deal only with signed accounts which have some months account age or with whom you dealt before. And better you do three trades with amount X instead of one trade with amount 3x. A
And when the trader with who he deals is caught because the banks are alerting the police a guy with no registered business is sending 10 wires a day to random people and they seize all the information from that bank guess whose name will be on one of those transactions?
Now I know why the police are able to seize that many coins and how so many people end up in court or jail, ignorance is truly bliss for some.