In the first of three reports on the murky world of electronic fraud, Go Digital's Tracey Logan investigates the "black money" scam.
It was 2 November 1999 when an American executive wired the sum of $742,000 dollars into a business account in the name of H Nsakala. This should have been the last he saw of his money.
The cash is supposedly dyed black to get through customs
Nobody knows how many experienced businessmen fall for the offer of a cool million or two, by e-mailers announcing themselves as corrupt Nigerian businessmen.
But by the time police get involved, victims have usually lost, not gained, more than £250,000, much borrowed from friends, families and even employees.
In the past 12 months, 15 cases have come to light in the City of London, a financial district measuring just one square mile.
These advance-fee frauds are also known as "419 scams", named after the section of the West African country's criminal code that prohibits fraud.
Across the capital, police have investigated over 100 similar crimes. But, because of their complex, international web of deceit, the criminals are hard to track down and, in most cases, victims will never see their money again.
So Detective Inspector Barry Bryan of the City of London Police Fraud Squad, could not believe his eyes last year when he spotted a Gold Visa card, bearing a photo of its owner, in the name of H Nsakala.
The credit card proved vital in the investigation
He told the BBC's Go Digital that proved to be a vital, evidential link, to an account in the same name used to defraud three businessmen in America, Hong Kong and Holland, out of a total $4.3 million dollars.
The bearer's real name is Monsuro Adeko, and police found him in possession of 162 credit and debit cards, 15 birth certificates, 38 driving licences and 22 British and Dutch passports.
Now serving nine years, the longest sentence ever obtained by the Fraud Squad, Adeko was convicted of multiple counts of conspiracy to defraud, forgery and counterfeiting.
Best of all for the victims, the judge ordered Adeko and his wife, also in prison for money laundering, to pay £948,582 in compensation to his victims.
Police seized their family home in Essex and a bond valued at £500,000 so victims will see most of their money again.
In a bizarre twist, one of the three businessmen had begun to think the fraudsters would finally deliver the promised millions.
But this was just another con, well known to police around the world as the black money scam.
Money for nothing
It is con that affects Norwegians in particular and, at a police convention last year, they demonstrated how it works.
The victim is told their money is waiting for them in a foreign country, such as Germany. On arrival, they meet their contact who opens a briefcase filled with black wads of paper.
These are $100 bills, according to the fraudster, dyed black to evade customs in their country of origin, usually somewhere in West Africa.
The victim watches as a black note from the case is sprayed with special chemical and, by sleight of hand, a $100 bill is produced.
A payment of just $50,000 will secure enough of the chemical to clean up the cash in the case.
"Of course, it's just water" said Detective Chief Inspector Kevin Moore of the City of London police, "and the black notes just worthless pieces of paper".
The best thing, say the police, is not to reply to any e-mails offering money for virtually nothing.
This could lead not only to a loss of funds, but a criminal prosecution for money laundering if you suspect the money might be the result of criminal activities.
"If an offer looks too good to be true then it generally is," said DCI Moore.
"If you can't afford to lose the money then don't get involved."
You can hear more about electronic scams and fraud on this week's Go Digital on the BBC World Service.