Elaina Aghayeva, an Azerbaijani national and senior neuroscience researcher at Columbia University, was detained by Department of Homeland Security agents at a university residential building on February 26-27, 2026. DHS agents entered without a warrant and falsely claimed to be searching for a missing child. DHS stated Aghayeva's student visa had been terminated in 2016 for failing to attend classes, though her attorney and the university stated she was a current student in good standing. After approximately nine hours in custody, Aghayeva was released following intervention by NYC Mayor Zohran Mamdani, who met with President Trump regarding the case. Aghayeva's attorney filed a habeas corpus petition in federal court, and the detention prompted student protests at Columbia University.