Porsche employees under investigation over diesel cars

German authorities are investigating employees of Porsche and a U.S. subsidiary, as a probe into Volkswagen's (OTC:VLKAY) alleged diesel emissions cheating continues.

Stuttgart prosecutors said Monday they are investigating suspicions of fraud and making false claims. They said that the investigation is against persons unknown who were employed by Porsche and a U.S. unit which it did not identify.

Prosecutors elsewhere in Germany are investigating alleged wrongdoing at Volkswagen and Audi, another of the German automaker's units.

Volkswagen has acknowledged equipping about 11 million cars worldwide with software that sensed when cars were on test stands and turned emission controls up, then turned the controls off during every day driving to improve performance.

The Associated Press contributed to this report.