Cell phone data expert and key witness take the stand in retrial of Karen Read

Jurors in Karen Read’s second murder trial heard more testimony Tuesday about location and temperature data recorded on her boyfriend’s cell phone the night she’s accused of killing him.

Jurors in Karen Read’s second murder trial heard more testimony Tuesday about location and temperature data recorded on her boyfriend’s cell phone the night she’s accused of killing him. Prosecutors say Read, 45, backed her SUV into Boston police Officer John O’Keefe, 46, after dropping him off at a party hosted by a fellow officer in January 2022 and left him to die in the snow. Defense attorneys say she was a victim of a conspiracy involving the police and have suggested he was killed by someone inside the home. A mistrial was declared last year after jurors said they were at an impasse. Read’s second trial on charges of second-degree murder, manslaughter and leaving the scene, began April 22 and has thus far looked similar to the first. Digital forensics specialist Ian Whiffin testified Monday that location data on O’Keefe’s phone was consistent with the device being near a flagpole on the lawn of the home from 12:32 a.m. onward, there was no activity after that and the temperature of the phone’s battery dropped from 72 degrees (22 degrees Celsius) at 12:37 a.m. to 37 degrees (2.8 degrees Celsius) at 6:14 a.m. Such data could suggest O’Keefe remained outside. But under cross-examination Tuesday, Whiffin testified that he observed a much more dramatic drop in temperature when he performed an experiment by placing a phone in a freezer. He also acknowledged that the phone could have been anywhere within a larger radius than he previously described but said that data was not as accurate.