FRANKFURT -- Volkswagen Group's headquarters in Wolfsburg, Germany, was raided by public prosecutors on Tuesday in the latest investigation into the automaker's diesel-emissions scandal.
Prosecutors said investigators aimed to confiscate documents.
VW said it was fully cooperating with the authorities but the company views the investigation as unfounded.
The raids were linked to an investigation into diesel cars with engine type EA 288, a successor model to the EA 189 which was at the heart of the automaker's test-cheating scandal.
VW admitted in 2015 to cheating U.S. emissions tests on diesel engines.
The automaker said it had itself disclosed the issue at the center of the new investigation, which is targeting individual employees, to the relevant registration authorities.
In simulations, vehicles with the EA 288 engine did not indicate a failure of the diesel filter, while still complying with emissions limits, Volkswagen said, adding the engine did not have an illegal defeat device.
VW's diesel cheating has so far cost the company about 30 billion euros ($33 billion) in fines, vehicle refits and legal costs, and also triggered a global backlash against diesel vehicles.
VW said when the scandal broke that about 11 million vehicles worldwide were fitted with the illegal software.