Mahmoud Khalil called himself a "political prisoner" in a new letter dictated from the Louisiana detention center where he remains held following his arrest.

Amy Greer, Khalil's attorney, said officials were acting on a State Department order to revoke Khalil's student visa and green card when he was arrested and detained. Khalil was sent to a detention center in Jena, Louisiana. He will not be present at the New York hearing, his lawyers said.