The chief executive of German carmaker Audi, Rupert Stadler, has been arrested in connection with an investigation into the diesel emissions scandal.
A spokesman for Volkswagen, which owns Audi, confirmed he was being held.
Munich prosecutors said they had acted because of a risk that Mr Stadler might seek to suppress evidence.
The devices were initially found in VW’s cars, but its Audi subsidiary has also been embroiled in the scandal.
Last month, it admitted that another 60,000 A6 and A7 models with diesel engines have emission software issues.
That is on top of the 850,000 recalled last year by Audi, of which only some have been found to require modification.