A top U.S. Justice Department official says the department is investigating whether Columbia University concealed “illegal aliens” on its campus.

I was a student at Columbia University, where I covered tense campus protests over the Israel-Hamas war for the college newspaper and for POLITICO. So I’m familiar with Mahmoud Khalil, a former Columbia student who I’ve chatted with in the past and appears to be the first target of the Trump administration’s effort to crack down on student protesters.