Lawyer Gary Miller of the International Fraud Group said the amount was "minuscule, a drop in the ocean" in a cybercrime industry estimated to be worth $1 trillion to $2 trillion.
He said it is "quite unusual" to track down a cyber-criminal because "they're usually protected by a few tens, if not hundreds, of zombie servers which hide their identity." His group traces looted funds for individuals and companies.
Nigeria is notorious for internet fraud. The U.S. Embassy says it receives inquiries every day from Americans who have been defrauded.