A former Apple Inc. engineer was arrested on charges of stealing driverless car secrets for a Chinese startup after he passed through the security checkpoint at San Jose International Airport to board a flight to China.

Xiaolang Zhang was accused by U.S. prosecutors of downloading files containing proprietary information as he prepared to leave the iPhone-maker in April and start work for Guangzhou-based Xiaopeng Motors, according to a criminal complaint filed Monday in federal court in San Jose, California.

A hardware engineer for Apple's autonomous vehicle development team, Zhang was granted access to confidential company databases, according to the complaint. After he took paternity leave, he told Apple in April he was moving back to China to work at Xmotors. Apple grew more suspicious after seeing his increased network activity and visits to the office before he resigned, according to the complaint.