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.

Judge Beverly Cannone is in charge of Karen Read's high-profile in Dedham, Massachusetts trial for a second straight year.

Here’s a look at a timeline of the entire case, from the key 6-hour period surrounding O’Keefe’s death and the ensuing legal battle over who is responsible.