German prosecutors said Monday they have opened a criminal investigation into Volkswagen's former chief executive Martin Winterkorn concerning his role in the massive pollution cheating scandal that has rocked the auto giant.

"Following a number of legal suits, the public prosecutors in Brunswick have opened an investigation against Martin Winterkorn, the former chief executive of Volkswagen. The investigation will focus on the allegation of fraud by selling vehicles with manipulated emission values," the prosecutors said in a statement.