“Put the person’s name into the internet” is one of the useful pieces of advice that you’ll find in this handy piece on avoiding online fraud on ThisIsMoney.
It’s well worth a read – and if you’re dealing with someone who’s in the UK, save yourself a bit of time by searching for them directly on 192.com people search.
Alternatively if you already have an address for someone, you could either get a full Background Report on them or, if you just want to verify their identity, you could try VouchID.
However you’re checking on people, make sure that you don’t get caught out by the fraudsters.