Four former VW execs go on trial over Dieselgate

Four former executives of German carmaker Volkswagen went on trial Thursday (September 15) over their role in the firm's emissions cheating scandal.

The case is being heard in the town of Braunschweig, near VW's headquarters.

Prosecutors say the four knew of the illegal software used to cheat emissions tests, but did nothing to address the issue.

Instead, they allegedly sought to maximize profits for the company, and as a result their own performance bonuses.

All four are charged with fraud.

The defendants either deny knowledge of the cheating, or say they informed superiors about it.

Former CEO Martin Winterkorn isn't among their number.

His trial will take place at a later date.

VW admitted cheating on U.S. tests in 2015, sparking the biggest crisis in its history.

So far the scandal has cost it almost $38 billion in vehicle refits, fines and legal costs.