Federal prosecutors in the United States have charged former Volkswagen chief executive Martin Winterkorn, accusing him of conspiring to mislead regulators about the German automaker's diesel emissions cheating.
The 70-year-old resigned soon after the scandal over polluting vehicles in the US became public in September 2015.
Attorney General Jeff Sessions said in a statement the charges allege "Volkswagen's scheme to cheat its legal requirements went all the way to the top of the company".
Mr Winterkorn is charged with conspiracy to defraud the US, wire fraud and violating the Clean Air Act from at least May 2006 to November 2015 by using illicit software that allowed VW diesel vehicles to emit excess pollution without detection.
Mr Winterkorn told German lawmakers last year that he had not been informed of the cheating early and would have halted it had he been aware. But he did not say when he first became aware.
VW had initially suggested that only lower-level executives knew of the cheating.
But the indictment alleges Mr Winterkorn was informed of the cheating in May 2014 and in July 2015 and he agreed with other senior VW executives "to continue to perpetrate the fraud and deceive US regulators", prosecutors said.
A spokeswoman for the US Attorney's Office for the Eastern District of Michigan in Detroit said Mr Winterkorn was not in custody.
In total, nine people have been charged and two former VW executives have pleaded guilty in the case and been sentenced to prison terms.
One Italian citizen, former Audi manager Giovanni Pamio, is in Germany awaiting extradition.
Last year, Volkswagen pleaded guilty to fraud, obstruction of justice and falsifying statements in Detroit as part of a $4.3bn settlement reached with the US Justice Department over the scandal and agreed to three years of oversight by a former US deputy attorney general.
In total, VW has agreed to spend more than $25bn in the US to address claims from owners, environmental regulators, states and dealers and offered to buy back about 500,000 polluting US vehicles.
