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.

A crazed Karen Read uttered a chilling question before she and two others found her Boston cop boyfriend dead in the snow, according to testimony from a key witness Tuesday. “Did I hit him?” Read kept asking,

Cellebrite expert Ian Whiffin walked jurors through one of the most contentious pieces of evidence in Karen Read’s case Monday.