German authorities have arrested Audi CEO Rupert Stadler as part of a probe into Volkswagen's emissions test cheating.
Mr Stadler (pictured) is the most senior company official to be detained so far since VW admitted in 2015 to using illegal software to rig U.S. emissions tests on diesel engines.
Munich prosecutors said he was being held due to fears he might hinder their investigation into the scandal.
The arrest has plunged the company into a leadership crisis just as VW group chief executive Herbert Diess was trying to introduce a new leadership structure.
'As part of an investigation into diesel affairs and Audi engines, the Munich prosecutor’s office executed an arrest warrant against Rupert Stadler on 18 June 2018,' the Munich prosecutor’s office said.
A judge in Germany ordered that Stadler be remanded in custody, it said, to prevent him from obstructing or hindering the diesel investigation.
Audi and VW confirmed to the press that the arrest had happened and reiterated Stadler was presumed innocent.
The news follows German authorities imposing one of the state’s highest ever fines on VW with a €1bn (£880m) charge for its diesel emissions cheating, as well as the US filing criminal charges against the former VW chief executive Martin Winterkorn in May.
However Germany does not extradite its nationals to countries outside the EU, making a prosecution in America unlikely.
VW has set aside around $30bn to cover fines, vehicle refits and lawsuits over its 'dieselgate' scandal. It has announced plans to spend billions more on a shift to electric vehicles.
The scandal, mounting fears over air pollution and a UK government ban on new diesel and petrol cars by 2040, has resulted in plunging diesel sales, which have fallen by 30% in 2018 compared with the same period in 2017.