Several people bid the woman goodbye as she tugged on her pink “Free Karen Read” T-shirt and left the rally, where sign-waving supporters gathered 30 minutes before the trial began.

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.