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.

ICE addressed the arrest of a criminal defendant mid-trial at Boston Municipal Court Central — but did not speak on contempt charges the judge filed against the agent.

The judge dismissed the case due to prosecutorial misconduct after ICE detained Wilson Martell-Lebron on the first day of his trial.