The Department of Homeland Security claimed that Columbia University anti-Israel activist Mahmoud Khalil “led activities aligned to Hamas, a designated terrorist organization."

Mahmoud Khalil, a 29-year-old legal resident of the United States, was arrested and detained by federal agents Sunday, after his green card was revoked by the Trump administration.

Khalil’s arrest could have a chilling effect on on- and off-campus protests involving people who aren’t citizens, said Columbia University immigration law professor Elora Mukherjee. Already, she said, it had provoked panic and fear among immigrant students on campus.