Former Audi CEO Rupert Stadler has been charged by German prosecutors over his alleged role in the Volkswagen Dieselgate scandal, along with three other defendants who were not named. Stadler is accused of helping the automaker cheat emissions tests to make Audi’s cars appear cleaner than they really were as well as covering up that fraud.

Stadler is the second high-profile Volkswagen Group executive to be hit with criminal charges in Germany; former Volkswagen CEO Martin Winterkorn was charged in April. (Winterkorn was also indicted in the United States in 2018.) Four top Audi managers were indicted by a grand jury in the United States in January, and two employees are in prison here as well.

The European Commission has also accused Volkswagen Group of colluding with BMW and Daimler (the parent company of Mercedes-Benz) of slowing the rollout of better emissions restriction technology.

Prosecutors arrested Stadler last year and held him for four months in pretrial detention for allegedly trying to obstruct their investigation. Audi postponed the launch of its first electric vehicle, the E-Tron, following his arrest, and it fired Stadler soon after. He joined Audi in 1990.

Audi “was more deeply involved” in Dieselgate than previously known

The charges come less than a week after The New York Times reported on how Audi “was more deeply involved” in hatching the emissions-cheating plan than previously known. Documents viewed by the Times show that engineers at Audi were discussing how to cheat US emissions tests as far back as 2003.

Volkswagen Group would go on to sell millions of cars with software that could detect when they were being run through the Environmental Protection Agency’s emissions tests. The software would restrict the emission of harmful nitrous oxide (NOx) to the allowed level during these tests. But when the cars were being driven under normal circumstances, they emitted up to 40 times more NOx.

Information made public in the January indictment showed that the cheat likely originated at Audi. Some of the automaker’s engineers concluded in 2006 that they would not be able to calibrate the company’s new diesel engine to meet both the NOx emissions standards in the United States and the desire of Audi executives to offer a “large trunk and a high-end sound system.” Instead, they were ordered to design a way to beat the emissions tests. A few engineers pushed back, but the company’s executives ultimately decided to move forward with the plan, according to the indictment.