The US Federal Bureau of Investigation, FBI, has spread its net in Nigeria tracking email scammers who network with their colleagues across the globe to cream individuals and corporates of billions of dollars.

The email scam is a hacking process in which the perpetrators hack into email accounts of key persons in an organization and mailing them with instructions to wire money from their company accounts to specified accounts controlled by the scammers.

The ascendancy of the cyber scam has compelled FBI to spread its dragnet across continents. Their effort has yielded results already with no fewer than 74 people already arrested in a global crackdown on email fraud scams.

The cases involve a growing type of fraud known as “business email compromise” that targets employees with access to corporate finances. The fraudsters send emails that appear to be from trusted corporate executives or vendors, which instruct targeted employees to wire funds to accounts controlled by criminals.

The same groups also ran similar scams targeting individuals, including real-estate buyers and the elderly, the bureau said.

Nearly $2.4 million was seized in the six-month operation dubbed “Operation Wire Wire” and about $14 million in fraudulent wire transfers was recovered, according to the U.S. Federal Bureau of Investigation.

Of those arrested, 42 were in the United States, 29 in Nigeria, and the others in Canada, Mauritius, and Poland, the FBI said.