It has been an open secret for years that any Chinese national
“student” is a de facto part of Chinese intel. The “Confucian Institutes” that flourished during the last 20 years were campus headquarters for Chinese subversion until closed by Trump in 2019.
I worked in an academic library that employed a Chinese there on a student visa/green card. He was a computer expert. Shortly after he was employed, he breached the security of the university mainframe. He seemed to be making regular reports to someone who called him in our office. He only spoke Chinese to this person in lengthy conversations that seemed only one-sided—him informing the other of something important.
He went over summer breaks back to Communist China, usually taking a laptop from the university that he loaded up with software/files before he left. I once saw him online with the Confucious Institute. In the evening before I left for home, he warned me not to shut down our shared office computer because he would be working, using it remotely. I don’t know what he was working on. I should have stayed in the office and watched him with the monitor on.
He was a pleasant person, not getting close to anyone, very polite and guarded. Once, however, he slipped and made an extremely negative remark about the CIA—suggesting it was spying on people in this country and was a malevolent force.
I was suspicious of him and should have watched him more closely.