US prosecutors charged 80 people -- mostly Nigerians -- in a widespread conspiracy on Thursday.
The scam defrauded at least $6 million from businesses and vulnerable elderly women.
According to CNN, 17 people have been arrested in the US so far.
Federal investigators are trying to track down the rest in Nigeria and other nations.
We believe this is one of the largest cases of its kind in US history. US Attorney Nick Hanna