Could face up to five years in prison.
Little is known about the investigation at this point but prosecutors are focusing on Winterkorn and an unnamed member of Volkswagen's Board of Management.
Sources say the investigation centers around "sufficient, real signs" that the company failed to properly disclose the possible financial damage of the Dieselgate scandal. The company acknowledged the presence of so-called defeat devices last September but it appears the company may have been in a position to warn investors prior to that date.
If convicted, Winterkorn and the Board Member could be forced to pay a fine or serve up to five years in prison.
Volkswagen downplayed the news by saying "today's press release from the Braunschweig public prosecution service does not cite any new facts or information on any serious breaches of duty by the members of the Board of Management now accused." The company went on to say an independent investigation by U.S. law firm Jones Day hasn't found any "serious and manifest breaches of duty on the part of any serving or former members of the Board of Management."
Source: Automotive News and Volkswagen