MUNICH -- German prosecutors said on Wednesday they had filed charges against former Audi CEO Rupert Stadler, who is being investigated for his role in Volkswagen Group's diesel-emissions cheating scandal.
The public prosecutor's office in Munich said Stadler and three other defendants are being charged with false certification and criminal advertising practices.
The three other defendants are accused of having developed engines used by Audi, Volkswagen and Porsche brand cars that included emissions-cheating devices, it added.
"Defendant Stadler is accused of having been aware of the manipulations since the end of September 2015, at the latest, but he did not prevent the sale of affected Audi and VW vehicles thereafter," the prosecutor said in a statement.
Once seen as a possible contender for VW Group’s top job, Stadler was arrested in June 2018 and spent months in jail. Audi, which had previously extended his contract, suspended him shortly after he was detained.
VW Group, which has faced billions of dollars in costs related to the scandal, later terminated Stadler's contract against the backdrop of a criminal investigation into whether he was involved in emissions tests cheating.
The accused include former Audi and Porsche manager Wolfgang Hatz as well as two engineers, several people familiar with the proceedings said.
Hatz, who is the former r&d chief at Porsche and former head of powertrain development at both Audi and VW Group, spent several months in custody in 2017 and 2018 over his alleged role in the scandal.
People familiar with the proceedings told Reuters that Stadler and Hatz have denied wrongdoing.
The prosecutors declined to identify the other defendants, while Stadler's and Hatz's lawyers were not immediately available for comment.
Investigations against 23 further suspects continue, the prosecutor's office said.
Stadler’s attorney Thilo Pfordte didn’t immediately reply to an email seeking comment, and Audi said it won’t comment beyond saying that all individuals should be presumed innocent until proven otherwise.
Audi, which is VW Group’s biggest profit center, quickly became implicated in the cheating affair, setting back VW Group's attempt to contain fallout. The focus turned to Stadler as prosecutors sought to untangle the origins of the scandal. In the years that followed, repeated recalls of Audi vehicles over their emission performance -- including Porsche cars with engines developed by the brand -- continued to taint the brand.
In April, prosecutors in Brunswick, Germany, charged former VW Group CEO Martin Winterkorn with serious fraud for his role in the diesel-rigging scandal that has so far cost the carmaker about 30 billion euros ($33 billion).
More investigations are pending, including a probe into market manipulation targeting current VW Group CEO Herbert Diess, Chairman Hans Dieter Poetsch and Winterkorn over allegations they informed markets too late about the diesel case and its effect. Volkswagen has said that it couldn’t have anticipated the dramatic fallout from the revelations.
Bloomberg contributed to this report