Volkswagen is struggling to draw a line under its biggest ever corporate crisis in which it admitted using illegal software to rig US diesel engine tests.

The “dieselgate” scandal has cost the German carmaker more than €32 billion in fines, refits and legal costs.

“In his testimony, the accused falsely claimed to have been informed of the defeat devices only in September 2015,” Berlin prosecutors said in a statement today, confirming an earlier report in Bild newspaper.

“According to the indictment, he had since May 2015 been aware that the engine control software of some VW vehicles had been equipped with a function to manipulate the exhaust values in testing,” the prosecutors added.

A spokesman for Winterkorn, who was Volkswagen CEO between 2007 and 2015 when he left the company, did not immediately respond to a request for comment.

Volkswagen said in late March said it would claim damages from Winterkorn for breaching his duty of care by failing to fully and swiftly clarify circumstances behind the use of unlawful software functions in some diesel engines.

Winterkorn resigned as CEO on Sept 23, 2015, a week after the scandal was uncovered.