John O’Keefe passed away after he fell backwards, striking his head on the frozen ground. This was revealed by a brain surgeon educated at Yale who provided testimony on Wednesday during Karen Read’s murder trial.

Karen Read, aged 45, is charged with the murder of her former boyfriend, 46-year-old O’Keefe. The incident occurred on January 29, 2022, and involved her allegedly hitting him with her 2021 Lexus SUV and subsequently leaving him to succumb to his injuries amidst a snowstorm in Canton, Massachusetts, approximately 20 miles south of Boston.

According to Dr. Aizik Wolf, who shared his expertise during the trial, the combination of head trauma and skull fractures O’Keefe suffered, alongside the effects of hypothermia from the severe cold, would not have resulted in immediate death. Dr. Wolf has treated numerous injuries of a similar nature throughout his career in Minneapolis.

“The only way he could get this kind of an injury was to fall backwards, hit the back of his head, and then the resulting energy forces going into his brain, into the base of his skull,” he told the jury during questioning from special prosecutor Hank Brennan. 

Defense attorney Alan Jackson had her explain that the only thing any of the bumper glass matched was a glass sample recovered by former Trooper Michael Proctor, who was fired in March after an internal probe into inappropriate text messages he sent during the investigation.

Earlier in the trial, the defense played video showing Proctor standing near the rear of the vehicle, out of camera view, while it was at the Canton Police Department headquarters.

Proctor, through his family, has maintained that his investigation was in line with the evidence and conducted with integrity.

Read could face life in prison if convicted of the top charge, second-degree murder. She is also accused of drunken driving, manslaughter and leaving the scene of a deadly accident.

Fox News’ Andrew Fone contributed to this report.