So say you have been duped by a Nigerian scammer and you contact the Nigerian police for help.
You might get an email apparently from the Nigerian police telling you they have closed in on the scammer and need a payment from you before they can arrest him.
Needless to say that is the last you will hear of your apparent fortune.
The money could be cash, gold bullion, blood diamonds, gold dust, checks etc.
The sums usually run up to millions of dollars with the victim being promised a huge chunk of it for their "help".
Instead of asking you to send them money for their ticket, they will instead send you scanned copies of a ticket to convince you they are genuine and are really coming to visit you.
They do not ask for money to buy the ticket or even for visa expenses… However, there is usually a last minute glitch and they will request you to send them a large amount of money without which the trip will be impossible.