Updated

A U.S. foreign service officer pleaded guilty in federal court Wednesday to accepting more than $3 million in bribes in exchange for visas that gave 500 foreign nationals entry into the country.

Michael Sestak, a State Department official, pleaded guilty to conspiracy, bribery and money laundering in a D.C. federal court. Under federal sentencing guidelines, he could be sentenced to 24 years in prison.

U.S. Attorney Ronald Machen Jr. says Sestak “corrupted the integrity of a process designed to screen visitors to the United States, a process that obviously has implications for our national security.”

Sestak was motivated by greed and “cold, hard cash,” Machen said.

According to court documents, Sestak personally raked in $3 million in the visa-for-cash scam, much of which he funneled into nine properties in Thailand.

The State Department was tipped off to issues with the visa vetting process in Vietnam -- where Sestak was stationed -- and referred the allegations to the Diplomatic Service Security to investigate.

Sestak was working as a non-immigrant visa chief in the Consular Section of the U.S. Consulate in Ho Chi Minh City, Vietnam from August 2010 to September 2012. His job required him to review visa applications, conduct in-person interviews and determine who got them.

Payments ranged from $15-$70,000 per visa, authorities said.

Sestak, 42, was arrested on May 13.

Four others have also been charged in the case.They include Binh Vo, 39, his sister Hong Vo, 27, who are both American citizens who had been living in Vietnam. Binh Vo’s wife, Anhdao Dao Nguyen, 30, and Truc Tranh Huynh, 29, were also charged. Nguyen and Huynh are both Vietnamese citizens.

As part of his plea agreement, Sestak admitted that he and Binh Vo worked together to come up with a plan to get money in exchange for visas.

Sestak conspired with other U.S. and Vietnamese citizens who recruited customers, authorities said.

The entire scheme brought in close to $10 million. Sestak’s personal stake was more than $3 million. He took the money and laundered through China into Thailand.

He has agreed to sell the Thailand properties and forfeit the profits.