Ah, found out how the bastards do it
There are some more letters here:
http://www.quatloos.com/cm-niger/nig...ter_museum.htm
This is what they do:
Participants in the scam, apparently, are asked to sign two forms, one authorizing the Nigerians to deposit the money to your account, and a second authorizing them to withdraw up to 70% of it. Of course, they only use the one authorizing withdrawals and clean out your account.
While most people only have a few hundred dollars in their accounts, This fraud, perpetrated hundreds of times over and over again, has apparently netted the crooks over US $100 million dollars. In Canada alone, the RCMP estimates these con artists have bilked Canadians of over $30 million.