Karen Read's second trial started Tuesday with opening statements and witness testimony in the Massachusetts murder case.

Karen Read’s second murder trial began Tuesday with a prosecutor saying the defendant’s own words will bolster evidence that she killed her police officer boyfriend three years ago and a defense attorney calling the case “the definition of reasonable doubt.

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.