
James Schaffer from Arizona and Jeffrey Kilbride from California, both 41-years-old, sent spam messages to promote pornographic websites, which netted the duo more than US$2 million.
"These men used a variety of tricks to try and hide their whereabouts from the US authorities, including logging-in remotely to servers based in Amsterdam to make their spam messages appear to be of non-US origin, and using bank accounts in Mauritius and the Isle of Man," said Graham Cluley, senior technology consultant for Sophos.
"The spammers worked hard to protect themselves and disguise their identities, but didn't lose any sleep over the hundreds of thousands of innocent families and children who were receiving their unwanted explicit emails," he added.
The pair now face up to five years in prison for each spam-related offence. In addition, the men could receive a US$50,000 fine and spend a maximum of 20 years in jail for money laundering.
Schaffer and Kilbride are due to be sentenced in September.