On the same day that Volkswagen agreed to plead guilty to three felony counts and pay fines totaling $4.3 billion to the Justice Department and Customs and Border Protection regarding criminal misconduct linked with the diesel scandal, the Justice Department confirmed that six executives have been charged over their own ties with the scandal.

On Wednesday, the six executives were charged with conspiracy to defraud the United States, defraud customers and violate the Clean Air Act. The charges are similar to those VW has pleaded guilty to.

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One of the six executives is Oliver Schmidt, who was arrested on Saturday while on vacation in Miami. The other five, believed to be in Germany, include Heinz-Jakob Neusser, the former R&D boss for the Volkswagen brand; Jens Hadler, head of engine development; Richard Dorenkamp, a supervisor on the engine development team; Bernd Gottweis, head of quality management; and Jürgen Peter, a liaison between regulators and the automaker.

Their case has been assigned to U.S. District Judge Sean F. Cox of the Eastern District of Michigan.

Volkswagen TDI 'clean diesel' television ad screencap

Volkswagen TDI 'clean diesel' television ad screencap

According to the charging documents and statement of facts filed with the court, the scandal dates back to 2006 when VW initially started work on a diesel engine to meet stricter U.S. emissions standards coming into force for the 2007 model year. Failing to meet the standards, the team in charge of developing the engine installed a piece of software, known as a defeat device, to hide the true level of emissions from regulators. The software was able to detect when a car was being tested in a lab and then turn on a low emissions, low performance mode.

In March 2014, West Virginia University’s Center for Alternative Fuels, Engines and Emissions published the results of a study commissioned by the International Council on Clean Transportation. The study identified substantial discrepancies in the emissions from certain VW diesel cars when tested on the road compared to when these cars were tested in the lab. It’s alleged that rather than telling the truth, the co-conspirators pursued a strategy to obfuscate the matter by providing testing results, data, presentations and statements that suggested the problem was due to innocent mechanical and technological issues.

None of the executives charged on Wednesday were members of VW’s management board, although several of them reported directly to the board.

“Volkswagen’s attempts to dodge emissions standards and import falsely certified vehicles into the country represent an egregious violation of our nation’s environmental, consumer protection and financial laws,” Attorney General Loretta E. Lynch said in a statement. “In the days ahead, we will continue to examine Volkswagen’s attempts to mislead consumers and deceive the government.”