Stadler's arrest also raises new questions about a Volkswagen response that's alternated between stonewalling and cooperation, while protecting its most senior managers.
Audi chief executive Rupert Stadler has been arrested in Germany over the software-enabled Dieselgate emissions scandal, according to reports. Munich prosecutors said Stadler's arrest was not made at the request of the U.S. Instead, it appears to be part of German prosecutors' widening probe into Audi.
A German judge has ordered that Stadler be remanded in custody.
The Chairman of Audi, Rupert Stadler, presents the new Audi concept vehicle Aicon at the 2017 Frankfurt Auto Show on September 12, 2017 in Frankfurt am Main, Germany.
A total of 20 people are under suspicion in the probe.
German officials investigating Dieselgate have circled Audi CEO Rupert Stadler like wary wolves for some time now, closing in.
Volkswagen has pleaded guilty to criminal charges in the United States.
But the saga has cast a wider pall over Germany's vaunted vehicle industry, shattering the myth of "clean diesel" and raising suspicions of emissions manipulation among other companies.
Last month VW admitted an additional 60,000 Audi A6 and A7 models with diesel engines had a defeat device - on top of the 850,000 recalled in 2017.
Standler's home was raided last week where Munich prosecutors based the arrest warrant on concealment of evidence.
Audi confirms CEO has been arrested but can not comment further on ongoing investigation.
Volkswagen declined 2.2 percent to 157.88 euros and traded 2 percent lower at 11:50 a.m.in local trading, extending losses this year to 5.2 percent. The probe is aimed at an unidentified Porsche board member, another member of its management and a third person who is no longer employed by Porsche.