The Congressional hearing was part of a federal investigation into so-called "sanctuary cities."Committee Chairman James Comer, a Republican from Kentucky, launched the probe back in January to look into what he described as "the policies of sanctuary jurisdictions and their impact on public safety and federal immigration enforcement.

The theatrical hearing reflected enormous tensions as President Donald Trump continues a major crackdown on undocumented immigration, with Democrats and Republicans sparring over the course of proceedings.

Boston Mayor Michelle Wu may be facing criminal prosecution for the city’s sanctuary policies after the prospect of federal charges was raised by numerous Republican lawmakers who grilled her at a