About 160 investigation officials have searched 10 buildings located in the German states of Bavaria and Baden-Wüerttemberg in the hunt for evidence linking the board member to emissions test manipulation.
The board member is one of three unnamed suspects involved, including an individual from a high management position and a former Porsche employee.
Porsche confirmed the investigation but did not comment on who was involved. It said in an official statement: "We confirm that investigators today inspected and secured documents at the offices of Porsche AG in Stuttgart and Audi AG in Ingolstadt.
“Audi AG and Porsche AG are co-operating fully with the investigating authorities. Please appreciate that we can’t comment on further details due to the ongoing investigation."
Although no further details about the search have been released, it is believed to be part of the wider investigation into Porsche’s involvement in Dieselgate. The brand’s link has so far centred on its use of Audi diesel engines.
Audi’s 3.0-litre V6 diesel engine, which has been used in more than 125,000 cars including the Porsche Cayenne, was found to feature emissions cheat software earlier this year. Audi's Ingolstadt and Neckarsulm premises were searched only last week.
No link has been made to the recent VW Group management shuffle, which replaced former CEO Matthias Müller with Herbert Diess. VW Group chairman Dieter Pötsch said the move sought to “safeguard” the company and its long-term strategy.
Porsche recently axed the last current diesel models from its line-up, but said the decision was due to demand and had no relation to the ongoing emissions scandal. The company said it will soon introduce a diesel version of the latest Cayenne.