Charges have been filed against eight more Volkswagen employees accused of involvement in the company’s diesel scandal.
Prosecutors in Braunschweig did not identify the eight, who they said include managers, citing German privacy rules.
They said the suspects are aged between 50 and 72 and face charges including perpetrating or participating in serious fraud at various points between 2006 and 2015, indirectly providing incorrect certification and breaching a law on unfair competition.
Some of them are also accused of breach of trust and tax evasion, or being accessories to those offences.
The scandal involved the sale of cars fitted with software that let them cheat on emissions tests.
It said four other defendants would face trial on charges of fraud in connection with aggravated tax evasion and illegal advertising.
Dates for that trial have not yet been announced.
Winterkorn resigned days after the US Environmental Protection Agency announced a notice of violation on September 18 2015.
The company had for years been using software that recognised when vehicles were on test stands and turned emission controls on, then turned the emission controls off during normal driving.
As a result, the cars emitted far more than the legal US limit of nitrogen oxide, a pollutant that harms people’s health.
Volkswagen paid more than 30 billion euros (£27 billion) in fines and settlements over the scandal.