GERMAN prosecutors have expanded their probe into Volkswagen’s diesel car emissions scandal, claiming they have evidence former CEO Martin Winterkorn may have known of the cheating earlier than he claimed.

The 69-year-old stepped down in September 2015, days after news emerged in the US of Volkswagen’s use of software which turned off emissions controls.

He said at the time that he was not aware of any wrongdoing on his part.

Winterkorn said before a parliamentary committee earlier this month that he first heard the term ‘defeat device’, the technical name for the illegal software, in September 2015 – even though US authorities had been pressing Volkswagen for months over emissions test discrepancies and the cheating had been going on for years.

Prosecutors in Braunschweig said that based on investigations, Winterkorn ‘could have known of the manipulative software earlier than publicly asserted by him’.

They have increased the number of suspects in their investigation from 21 to 37 people, with 28 locations including offices and private homes searched in Germany last week.

Winterkorn and others are now being investigated over allegations they committed fraud.

In a June statement, prosecutors said Winterkorn was being investigated only over market manipulation for not making a timely disclosure of the possible financial consequences of the problem.

US prosecutors have separately charged seven former Volkswagen employees.

The company has agreed to pay £3.4bn in fines to settle criminal charges and reached a £11.8bn civil settlement in the US with environmental authorities and car owners.

The software enabled the car to detect when it was on the test stand and turn on emission controls, and then to turn them off during normal driving.

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