The former chief executive officer of Volkswagen, Martin Winterkorn, has been indicted by US prosecutors on charges related to the emissions cheating scandal.
Winterkorn stepped down from Volkswagen AG in 2015 after it was revealed that the automaker had been cheating emissions tests for years to bypass emissions regulations and limits worldwide.
At the time, Winterkorn said he was "stunned that misconduct on such a scale was possible in the Volkswagen Group," and while the former CEO denied any knowledge of such wrongdoing, was ready to accept "responsibility for the irregularities that have been found in diesel engines."
The emissions scandal involved Volkswagen "clean diesel" engines and a number of vehicle models, also produced by Audi.
So-called "defeat devices" were installed in these vehicles which would ensure that allowable levels of pollution and nitrogen oxides would be read in laboratory conditions and testing -- but out on the road, the automaker's vehicles would produce levels of pollution which are far beyond what is permitted.
In some cases, pollution levels would be up to 30 times higher than US laws permit under the Clean Air Act.
The 70-year-old has now been indicted by the US Department of Justice (DoJ).
The indictment alleges that Winterkorn, alongside five other Volkswagen executives, conspired to defraud the United States, conspired to commit wire fraud, and also conspired to violate the Clean Air Act.
US prosecutors allege that the executives "unlawfully enriched Volkswagen and themselves by deceiving US regulators in order to obtain the necessary certificates to sell diesel vehicles in the US; sold Volkswagen diesel vehicles to US customers knowing that those vehicles were intentionally designed to detect, evade, and defeat US emissions standards; and deceived US customers by marketing Volkswagen diesel engines as "clean diesel" and otherwise environmentally friendly."
The DoJ further alleges that due to this conspiracy, roughly 585,000 vehicles sold in the United States between 2009 and 2015 were equipped with defeat devices.
Winterkorn was allegedly well aware of the scheme, and according to prosecutors, went as far as approving a strategy to come up with good answers to questions posed by investigators.
"On or about 27 July 2015, in a meeting in Wolfsburg, Germany, VW employees briefed Winterkorn and other VW executives regarding the status of Model Year 2016 vehicles and a proposed strategy for dealing with US regulators [...] at that meeting, Winterkorn approved the continued concealment of the cheating software from US regulators," the indictment reads.
Volkswagen has pleaded guilty to criminal charges issued by the DoJ and agreed to pay up to $4.3 billion in fines, as well as launch a new clean energy initiatives.
In total, close to 11 million vehicles worldwide have been recalled to have their defeat devices removed.
See also: Volkswagen engineer sentenced over emissions cheating scandal
However, the DoJ isn't finished pursuing individual executives and engineers for their roles in the scheme.
In December, former Volkswagen general manager Oliver Schmidt was fined $400,000 and given a seven-year prison sentence for being heavily involved in the scandal.