Federal agents arrest Palestinian activist Mahmoud Khalil

Federal agents arrested Mahmoud Khalil, a Palestinian activist and Columbia University graduate student, in a video released on Friday. The arrest occurred in his apartment building lobby, alarming free-speech advocates and prompting concerns among international students. Khalil, a lawful U.S. resident, had his permission to stay revoked due to his involvement in pro-Palestinian protests. The Justice Department is investigating whether Columbia University concealed students sought by immigration authorities. Khalil's lawyers have challenged his detention, describing harsh treatment during his transfer to a detention center in Louisiana. He is now isolated and worried about his pregnant wife and missing the birth of their child.