The head of Volkswagen’s luxury arm Audi was arrested on Monday, the most senior company official so far to be taken into custody over the German carmaker’s emissions test cheating scandal.

“As part of an investigation into diesel affairs and Audi engines, the Munich prosecutor’s office executed an arrest warrant against Mr Professor Rupert Stadler on June 18, 2018,” the Munich prosecutor’s office said in a statement.

A judge in Germany has ordered that Stadler be remanded in custody, it said, to prevent him from obstructing or hindering the diesel investigation. Audi and VW confirmed the arrest and reiterated there was still a presumption of innocence for Stadler. Stadler himself was not immediately available for comment.

A spokesman for Porsche SE, the company that controls VW and Audi, said Stadler’s arrest would be discussed at a supervisory board meeting on Monday.