A Volkswagen AG engineer on Friday pleaded guilty and agreed to cooperate in the Justice Department’s probe into the German automaker’s diesel emissions scandalthe first person charged by U.S. authorities in the environmental probe.

James Liang, who has worked for VW vlkpf since 1983 and was part of a team of engineers who developed a diesel engine, was charged in an indictment made public on Friday with conspiring to commit wire fraud and violating U.S. clean air laws.

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The 62-year-old engineer from Newbury Park, Calif., appeared in U.S. District Court in Detroit on Friday and entered into a plea agreement that includes his cooperation with the government in its investigation. The indictment says Liang conspired with current and former VW employees to mislead U.S. regulators about the software that allowed the automaker to evade American emissions standards.

VW has already agreed to spend up to $16.5 billion to address environmental, state, and owner claims in the United States.

Liang was indicted in June, but the indictment was only made public on Friday.