In federal court in San Jose on Monday, Xiaolang Zhang, a former employee of Apple who was charged with stealing computer files containing trade secrets concerning the company’s highly-guarded automobile division, entered a guilty plea.

According to documents filed with the court on Monday, Zhang’s plea deal with the US government is confidential. Zhang pleaded guilty to a felony charge of theft of trade secrets and now faces up to 10 years in prison and a $250,000 fine. November is the date set for sentencing.

Zhang was charged with obtaining 25 pages of internal Apple documents that included circuit board engineering drawings for the company’s autonomous vehicle project. Zhang was also charged with stealing PDFs and reference books outlining Apple’s prototypes and their specifications.

At the San Jose airport, where he was scheduled to board a flight to China, Zhang was detained by federal investigators in July 2018. According to court papers from the FBI and U.S. attorney’s office, he had previously worked for Apple since 2015, most recently as a hardware engineer on Apple’s autonomous vehicle team.

The allegations provided a glimpse into Apple’s section that is working on autonomous electric vehicles, a secretive aspect of the firm that it still seldom acknowledges years later.

According to an FBI agent who testified in the 2018 charging filings, the corporation had 2,700 “core personnel” with access to project materials and databases in addition to around 5,000 “disclosed” employees who were aware of the project.

According to the complaint, Apple employs internal software to keep track of whose personnel are disclosed on which projects and mandates that they attend in-person secrecy training. Zhang contributed to the Compute Team of the autonomous vehicle project, which created and tested circuit boards for sensors.

Among the most important trade secrets in the electronics business are schematics for circuit designs.

After Zhang took paternity leave and visited China, Apple became suspicious that he was stealing trade secrets. According to the 2018 complaint, when he returned to the company, he submitted his resignation and stated that he wanted to return to China to care for his mother.

His connection to Apple’s network was suspended when he informed the corporation that he intended to work for Xmotors, a major producer of electric vehicles in China.

According to the complaint, an Apple investigation revealed that Zhang had downloaded files and data from corporate databases. According to the complaint, Apple’s closed-circuit cameras even caught Zhang entering the labs and removing electronics, later identified as circuit boards and a Linux server.

Jizhong Chen, another former employee of Apple, is also charged with allegedly stealing trade secrets from the company’s electric car division in the early months of 2019. In such situation, Chen, an American citizen, also had trip plans to China. Chen is being defended by the same attorney as Zhang and has not entered a plea of guilty. There is no definite date for the trial.

A request for comment from Zhang’s counsel went unanswered. Requests for response from Apple representatives were not answered.