The former CEO of embattled car company Volkswagen (VW) is being investigated by German prosecutors for his role in the company’s diesel emissions scandal.

According to the State Prosecutor’s office there was “sufficient concrete evidence” that Volkswagen had deliberately delayed informing shareholders of last year’s emissions scandal and the potential financial damage it could cause, The Guardian reports.

The investigation will focus on two former VW executives, including CEO Martin Winterkorn, who resigned in September after eight years at the helm.

The second executive has not been named, but in total 17 former VW employees are being investigated on suspicion of fraud.

The company has admitted that Winterkorn was informed of the illegal emissions at least a year before it was revealed to shareholders, having been sent a memo detailing the cars’ higher nitrogen oxide emissions in May 2014.

In addition, it has been revealed that European commission experts issued warnings about potential emissions test cheating as far back as 2010.

Companies registered on the stock exchange are obliged by law to inform investors of previously unknown events or circumstances that could considerably influence the price of shares.