Five people have been arrested by the Federal Bureau of Investigation (FBI) for their involvement with email hacking websites.
In an operation that also involved law enforcement agencies in Romania, India and China, US federal prosecutors charged two operators of hacking sites and three customers.
Mark Townsend and Joshua Tabor, both from Arkansas, were charged with a felony violation for operating the website needapassword.com. They each face a potential prison sentence of five years.
In a statement on Friday the FBI revealed that nearly 6,000 email accounts may have been compromised by Townsend and Tabor.
Customers to the site reportedly provided the pair with the names of email accounts that they wanted the passwords for, which they then paid for through PayPal.
The three customers, all from the United States, were charged with computer fraud offences for hiring computer hackers and each face up to one year in federal prison.
"These charges are the product of an international investigation coordinated by the Federal Bureau of Investigation, which received the assistance of the United States Air Force/Office of Special Investigations and the Naval Criminal Investigative Service," the statement said.
"During the investigation, the FBI coordinated with the Directorate for Investigating Organized Crime and Terrorism (DIIOCT) and Directorate for Combating Organized Crime (DCCO) of Romania, the Central Bureau of Investigation (CBI) of the Republic of India, and the Ministry of Public Security (MPS) in the People's Republic of China."
The international investigation resulted in four further arrests in Romania, one in India and one in China in connection with other sites offering hackers for hire.