Federal prosecutors have charged 15 people with impeding federal agents during a massive immigration surge in Minnesota earlier this year.

U.S. Customs and Border Protection has opened an internal investigation into whether the one-time architect of President Donald Trump’s large-scale immigration crackdown made disparaging comments about the Jewish faith while criticizing the U.S. attorney for Minnesota.

A federal judge has clashed with Minnesota’s top federal prosecutor in what he called a series of “testy and frosty” exchanges.