German public prosecutors raided the Wolfsburg headquarters of Volkswagen on Tuesday in the latest investigation into the carmaker’s diesel emissions scandal.

Prosecutors said investigators aimed to confiscate documents. Volkswagen, which admitted in 2015 to cheating United States emissions tests on diesel engines, said it was fully cooperating with the authorities, but viewed the investigation as unfounded.

Volkswagen said 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 test cheating scandal.

The carmaker said it had itself disclosed the issue at the center of the new investigation — which is targeting individual employees — to the relevant registration authorities.