Immigration agents arrest Palestinian activist who helped lead Columbia University protests. NEW YORK (AP) — Federal immigration authorities arrested a Palestinian activist Saturday who played a prominent role in Columbia University’s protests against Israel, a significant escalation in the Trump administration’s pledge to detain and deport student activists. Mahmoud Khalil, a graduate student at Columbia until this past December, was inside his university-owned apartment Saturday night when several Immigration and Customs Enforcement agents entered and took him into custody, his attorney, Amy Greer, told The Associated Press.