A man was arrested on the first day of the high-profile Karen Read trial inside the court-mandated "buffer zone" that is aimed at keeping people pushed back away from Norfolk Superior Court.

Karen Read pleaded not guilty to murder charges in the death of Boston police officer John O’Keefe and is facing a retrial after a jury was unable to reach a verdict last year.

Opening statements in Read’s murder trial will be held Tuesday, more than three years after O’Keefe’s death rocked the town of Canton and launched a sprawling legal saga that has since captured the nation.