There are big and small crooks out there.Caveat Emptor--let the buyer beware.
A buyer must carry out such checks as can reasonably be accessed and a seller must disclose, not conceal, information which if the buyer was aware of it would lead to him withdrawing.
There is much good advice on this Forum but that should not prevent the purchaser from carrying out "due diligence"
Always check what you are being told.
Good hunting.