Former VW CEO Martin Winterkorn resigned after claiming to have no knowledge of the diesel cheat devices.

Martin Winterkorn, the former CEO of Volkswagen AG, was charged in U.S. District Court in Detroit today, for conspiring to defraud the United States and violating the Clean Air Act, for his role in the automaker’s efforts to cheat on diesel emissions standards.

VW officials did not comment on the indictment, which was filed in secret in March and unsealed today. Several executives were named in the indictment. Winterkorn, the highest-ranking executive charged, was cited for trying to mislead regulators about the cheating.

When the scandal broke in 2015, then-CEO Winterkorn denied having knowledge of the efforts by VW engineers to use a device and software to pass emissions inspections. 

The U.S. Environmental Protection Agency accused VW of using a so-called “defeat device” on its 2.0-liter turbodiesel. The automaker subsequently acknowledged the subterfuge, while also admitting it rigged a higher-end 3.0-liter engine, as well.

(Former VW CEO under increasing scrutiny over emissions scandal. Click Here for the story.)

He resigned not long after the scandal became public in September 2015, maintaining he had no prior knowledge of the effort.

“As CEO I took political responsibility,” the 69-year-old Winterkorn said during a German parliamentary inquiry in January 2017, adding that, “this step was the most difficult of my life.”

VW admitted in September 2015 that it outfitted about 11 million diesel cars worldwide with a defeat device, embedded software that permitted vehicles to recognize when they were being tested in laboratory conditions, and to reduce emissions to meet acceptable levels.

(Click Here to see the examination of Martin Winterkorn’s role in the diesel scandal.)

According to the indictment, Winterkorn was told of the problem and questioned how U.S. regulators were threatening to delay certifying 2016 cars for sale, at a July meeting in Wolfsburg, Germany, where the company is based, according to Bloomberg News.

The automaker pleaded guilty in January 2017 to using false statements to import cars into the U.S. and to obstructing investigations, and paid $4.3 billion in penalties. Worldwide, Volkswagen has paid more than $30 billion in fine, fees and penalties to resolve the issue.

(For the latest on the VW criminal settlement, Click Here.)

Additionally, two other employees pleaded guilty for their involvement, and five other executives have been indicted by the U.S. and remain in Germany, avoiding arrest, Bloomberg notes.