Key evidence in Karen Read trial

Karen Read, who is accused of causing the death of her Boston police officer boyfriend, is being retried in Massachusetts. Read has been charged with second-degree murder, manslaughter and leaving the scene. A mistrial was declared last year after jurors said they were at an impasse. CNN’s Jean Casarez breaks down key evidence.

​ Karen Read, who is accused of causing the death of her Boston police officer boyfriend, is being retried in Massachusetts. Read has been charged with second-degree murder, manslaughter and leaving the scene. A mistrial was declared last year after jurors said they were at an impasse. CNN’s Jean Casarez breaks down key evidence. Read More Breaking News, Latest News and Videos | CNN