President Trump's bid to keep Alina Habba in charge of the U.S. attorney's office in N.J. faces a new test after a defendant filed a motion challenging her authority.

Federal court hearings, grand jury proceedings and plea deals were abruptly canceled in New Jersey over questions about whether Alina Habba, the acting U.S. attorney, was legally appointed.

The Trump administration appeared to use legal loopholes to keep Habba in the role—which are already being used by criminal defendants to get them out of their indictment.