A former United States Foreign Service officer was sentenced to 64 months in prison after he was caught selling U.S. visas on the black market in Vietnam for up to $70,000.

The scam, involving a handful of people who process a total of 500 fake visa applications – all of them were granted – netted over $9 million during its two-year operation, according to the Washington Times.

The suspect, Michael T. Sestak, was sentenced on Friday at a federal court in Washington. Sestak pleaded guilty to participating in the conspiracy, which saw him collect more than $3 million in proceeds that were allegedly laundered through China into Thailand.

Sestak served as the non-immigrant visa chief in the U.S. Consulate in Ho Chi Minh City for more than two years from August 2010 to September 2012. Applicants have paid $15,000 to $70,000 for visas under the conspiracy. Three other people also pleaded guilty, according to Arkansas Online.

"As a Foreign Service Officer, Michael Sestak should have been upholding his responsibilities to the United States, not illegally cashing in by collecting over $3 million in bribes to short-circuit our visa process," acting U.S. Attorney Vincent Cohen said in a statement, NBC News reported.

Cohen added: "Because of this defendant's selfish greed, nearly 500 foreign nationals were able to enter the United States without the proper screening. This sentence reflects the seriousness of his corrupt conduct."