Volkswagen (VLKPF) CEO Matthias Müller is facing investigation in connection with the auto giant’s emissions-cheating scandal.
Prosecutors in Germany are trying to determine whether Müller, along with other key executives 0n Volkswagen’s board, deliberately withheld information about the company’s financial liabilities stemming from the scandal over “cheat devices” installed in its diesel-engine cars, Marketwatch reports.
Prosecutors said Müller, along with former Volkswagen CEO Martin Winterkorn and current Porsche (PORSCHE-AUTOMOBIL-HOLDING-SE) chairman Hans Dieter Poetsch—all on the management board of Volkswagen and the supervisory board at Porsche at the time—knew that U.S. environmental regulators were looking into the auto maker’s diesel-emissions months before the issuance of a public “notice of violation” on Sept. 18, 2015. It is alleged that they did not disclose these inquiries to investors, nor did they disclose possible Volkswagen or Porsche liabilities should the U.S. instigate a formal investigation.
By the time Volkswagen published a warning to its shareholders on Sept. 22 that year, the company’s stock value had already plunged 38%, Marketwatch reports.
For more on Volkswagen, watch Fortune’s video:
The automakers insist they fulfilled their financial disclosure obligations in a timely fashion and said the prosecutors charge is unfounded, Marketwatch reports, citing a spokesperson for Porsche.
The probe—which will not necessarily result in charges or convictions for any of the executives under investigation—may embolden thousands of investors seeking to claim in excess of $8.9 billion in damages from Volkswagen.