The first time that 35-year-old Zhang Lelin, a software engineer from China, felt uncomfortable in Silicon Valley was last year when he heard that a “huge team” of FBI agents had raided the home of one of his Chinese neighbours. 

The target, Zhang Xiaolang, was accused of stealing secrets when he left Apple to join a Chinese electric-car start-up and now faces 10 years in prison. Zhang Lelin says the drama had been “like a movie” and wonders if it was engineered to “send out a message” to other Chinese tech workers.

His worries have been compounded not only by other high-profile cases of Chinese IP theft, but by the increasingly antagonistic relationship between Washington and Beijing. The darkening climate has rattled Chinese companies, investors and — most of all — employees in Silicon Valley.