Germany expands diesel probe, includes Volkswagen board chairman

German prosecutors have widened their investigation Sunday into Volkswagen’s handling of the emissions scandal to include its board chairman, Hans Dieter Poetsch.

According to CBS News, Poetsch was VW’s chief financial officer when the company’s efforts to rig cars to cheat on U.S. diesel emissions tests became public in September 2015.

In a statement, VW said prosecutors in the German city of Braunschweig are investigating three members of the board including Poetsch. Prosecutors were already investigating former Volkswagen CEO Martin Winterkorn and VW brand chief Herbert Diess over allegations they didn’t inform investors soon enough.

VW rejects those allegations, but said they will continue to cooperate with investigations.

German law requires publicly traded companies to inform investors when they become aware of unforeseen developments that could affect the buying or selling of stock.