At least 30 managers were reportedly involved in the Volkswagen "dieselgate" affair, which saw the company install special software on its EA189-engined diesel cars to fraudulently pass emissions testing.
Der Spiegel has seen documents from an internal investigation commissioned by Volkswagen and run by law firm Jones Day.
According to the German newspaper, at least 30 managers were involved in approving and covering up the software, which allows up to 11 million cars with the EA189 diesel engine to cheat its way past emissions testing. A Volkswagen spokesperson told the newspaper that "the number is without foundation".
An anonymous source involved with the investigation told the publication that the group of active and passive collaborators could yet expand as the audit progresses. A manager told Der Spiegel that engine developers should have been "leery" as the EA189 motor somehow conformed to emissions standards without the need for expensive emission control features.
If true, the results of the internal investigation directly contradict sworn testimony given by Michael Horn, chief of Volkswagen's American operations.
Last week, Horn told the House of Representatives oversight and investigations committee on energy and commerce that "to my understanding, this was not a corporate decision, this was something individuals did" and that it was the work of a "couple of software engineers".
Volkswagen and Audi Australia have launched local websites that allow customers to see if their cars are affected.