A Nigerian accused of scamming $60 million from companies around the world through fraudulent emails has been arrested after months of investigation, Interpol and Nigeria's anti-fraud agency said Monday.

One target paid out $15.4 million, according to a statement.

The statement said the ringleader of a global scamming network, identified only as a 40-year-old called Mike, was arrested along with a 38-year-old accomplice in Nigeria's oil capital, Port Harcourt, in June. He is on administrative bail, which implies that officers do not yet have enough evidence to charge him in court.

The man is accused of leading a criminal network that compromised email accounts of small and medium-sized businesses around the world including in the United States, Australia, Canada, India, Malaysia, Romania, South Africa and Thailand. The statement didn't name any of the targets.

The network involved about 40 people in Nigeria, Malaysia and South Africa who provided malware and carried out the frauds, with money-laundering contacts in China, Europe and the United States providing bank account details.

A supplier's email would be compromised and fake messages sent to a buyer with instructions for payment to a bank account under the network's control, the statement said. Or the email account of a high-level executive would be taken over and a request for a wire transfer sent to an employee responsible for handling such requests.

Such crime "poses a significant and growing threat, with tens of thousands of companies victimized in recent years," Noboru Nakatani, executive director of the Interpol Global Complex for Innovation, said in a statement. "The public, and especially businesses, need to be alert to this type of cyber-enabled fraud."

Nigeria is notorious for internet fraud. The U.S. Embassy says it receives inquiries every day from Americans who have been defrauded.