Audi's chief development officer, Stefan Knirsch, stepped down "from his position with immediate effect" and would leave the company, Audi said in a statement on Monday.

With this move, 50-year-old Knirsch became the second Audi development chief to resign in less than a year. Knirsch, who joined Audi in 1990, had held the position for just 10 months. Prior to that, he had led the group's engine development unit.

Audi said Knirsch was "leaving in agreement with the supervisory board" but did not elaborate on his reason for quitting.

The resignation came after Germany's "Bild am Sonntag" newspaper reported last week that an internal investigation by US law firm Jones Day had found that Knirsch knew that Audi's 3.0-liter diesel engines were equipped with cheating software before the scandal erupted.

He is also reportedly suspected of having made false declarations about his knowledge of the matter.

Reeling under the scam

He is the latest executive of the VW group to have stepped down after Volkswagen's emissions cheating scam came to light last year, when the Wolfsburg-based company admitted to installing "defeat devices" in 11 million diesel vehicles worldwide.

The sophisticated software could detect when the cars were undergoing regulatory tests and lower their emissions accordingly to make them seem less polluting than they were.

Since then, the scandal has widened to include German auto supplier Bosch and Audi, which is one of the key profit pillars of the VW group.

In particular, Audi has admitted that the emissions manipulation software was installed in its 3.0-liter V6 diesel engine.

After the scandal erupted, VW roped in Jones Day to conduct an independent investigation into the scandal, which at one point led to the carmaker's shares falling by about 40 percent.

Its share price still remains over 20 percent lower than it was before the crisis erupted. Furthermore, the company has had to set aside billions of dollars to cover costs and fines related to the scandal.

sri/hg (dpa, AFP)