Experts said it is ordinary for immigration authorities to detain defendants outside courthouses before or after pretrial hearings. But several had never heard of agents disrupting an ongoing trial.

The standoff between ICE and Massachusetts law enforcement comes from a 2017 law preventing the latter from assisting federal agents—a so-called sanctuary policy. The rule has meant that some known illegal immigrant criminals have been released into communities without ICE's knowledge despite placing detainers on these individuals.

BOSTON (AP) — A judge in Boston is holding a U.S. Immigration and Customs Enforcement agent in contempt after he detained a suspect while the man was on trial.