Things to know about the retrial of Karen Read in the killing of her police officer boyfriend

A brain surgeon testified at Karen Read’s second murder trial Wednesday that the victim’s skull was most likely fractured when he fell backward and hit his head.

Read, 45, is accused of backing her SUV into her boyfriend, Boston Police Officer John O’Keefe, 46, and leaving him to die on a snowy night in the front yard of another officer’s home after she dropped him off at a party there in January 2022. Her lawyers say she was framed in a police conspiracy and that someone inside the home that night killed him.

A mistrial was declared last year. Read’s second trial on charges of second-degree murder, manslaughter and leaving the scene has so far appeared to follow similar contours to the first.

Neurosurgeon describes O’Keefe’s injuries

Dr. Aizik Wolf, director of the Miami Neuroscience Center, testified about reviewing photos of O’Keefe and his autopsy report. He described a ‘‘classic blunt trauma injury" and said he believes O’Keefe struck his head on the ground.

‘‘My opinion is that’s what caused this whole injury,’’ Wolf said. ‘‘The only way he could get this kind of an injury was to fall backward, hit the back of his head."

Asked by prosecutor Hank Brennan whether the injuries were consistent with being attacked with a bat or other object, Wolf said no, because O’Keefe had a ‘‘nondepressed skull fracture.’’

Putting the pieces together

Christina Hanley, a state police crime lab analyst, also testified Wednesday. She described examining a broken drinking glass and pieces of glass and plastic found near O’Keefe’s body, bits of plastic recovered from his clothing, pieces of glass found on the bumper of Read’s SUV and the vehicle’s broken taillight.

Several pieces of glass found on the ground matched the drinking glass, she said, and red and clear plastic found on O’Keefe’s clothing was consistent with the taillight.

Jurors face questioning

Wednesday’s testimony was delayed for about two hours after Judge Beverly Cannone said an issue had come up that required her to speak to each juror individually. She did not explain the issue, but after speaking to jurors, reminded them of the importance of not discussing the case with anyone or allowing anyone to try to discuss it with them.

On the witness stand for a second day Tuesday, digital forensics analyst Shanon Burgess was questioned by Read’s attorney about ‘‘trigger’’ events recorded by her Lexus SUV, including a three-point turn and backing up.

‘‘None of the information in that black box ... indicates there was a collision on January 29?’’ asked attorney Robert Alessi.

‘‘Not by itself,’’ Burgess answered.

‘‘Are Lexus SUVs trigger-happy?’’ Alessi asked.

‘‘I do not know, sir,’’ Burgess said.