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 Democratic mayors of Denver, Chicago, Boston, and New York City were grilled for hours over their so-called sanctuary city policies at a Congressional hearing Wednesday as President Donald Trump pushes his aggressive immigration agenda and threatens to punish cities that don’t comply.

Boston Mayor Michelle Wu will take questions regarding sanctuary city policies from Congress on Wednesday amid a recent spar with border czar Tom Homan.