A former member of the Cuban intelligence agency was arrested on Wednesday by federal agents who said he fraudulently obtained a green card to live legally in the United States. The U.S. Department of Homeland Security announced the man’s arrest but did not disclose his name.

Experts say there has to be a legal basis to revoke a person’s residency status, and removal needs to be ordered by an immigration judge.

Here's a look at what kind of protections foreign students and green card holders have and what might be next for Khalil.