German authorities have detained Audi chief executive Rupert Stadler in connection with the diesel emissions scandal.
A Volkswagen spokesman confirmed to the BBC that Stadler is being held.
Munich prosecutors are reportedly worried that Stadler might hide evidence and were set to question him on Thursday.
Volkswagen was found to have installed emission cheat devices in its vehicles three years ago, but its Audi subsidiary has also been caught up in the issue.
About 60,000 A6 and A7 models were reportedly found to have emission software issues last month, on top of a further 850,000 Audis recalled last year Only some needed modification, the BBC reports.
