On Monday morning, the jury heard detailed and technical testimony about cellphone data, which the prosecution is using to try to establish John O'Keefe’s location before he was found unconscious in the snow outside the Canton home.

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

Jurors in Karen Read’s second murder trial traveled Friday to the site of John O’Keefe’s death in 2022. Read is accused of killing O’Keefe, her boyfriend and a Boston police officer, with her vehicle and leaving him in the snow outside a house in Canton,