FRANKFURT, Germany — Former Volkswagen Group CEO Martin Winterkorn went on trial Tuesday on charges of fraud and market manipulation in connection with the corporate scandal over Volkswagen’s use of rigged software that let millions of cars cheat on emissions tests and emit high levels of harmful pollutants.

Prosecutors say Winterkorn knew about the illegal software well before the U.S. Environmental Protection Agency announced its discovery of the violation in September 2015. He has said he learned about the practice only shortly before the announcement and earlier testified during civil proceedings that the allegations against him “are not correct.”

Winterkorn, 77, was scheduled to go on trial in 2021 but his case was postponed due to health issues. — Associated Press