Updated 6/12/25 2:24 p.m.

DEDHAM, Mass. (WBZ NewsRadio) — The defense rested its case Wednesday in the Karen Read murder retrial. Closing arguments are set for Friday at Norfolk Superior Court in Dedham.

Read is accused of hitting her boyfriend, Boston Police Officer John O’Keefe, with her SUV and leaving him to die in the snow on Jan. 29, 2022. Read’s defense team has claimed she is innocent and is being framed.

ARCCA Witness Dr. Andrew Rentschler Testimony

ARCCA witness Dr. Andrew Rentschler returned to the stand when testimony began on Wednesday morning. The crash expert and biomechanical engineer was the defense's final witness. While there was some speculation that Read herself would take the stand, CBS News Boston reported that she would not testify in the retrial. She did not testify in the initial trial either, but the prosecution did submit interview clips with Read as evidence this time around.

Defense attorney Alan Jackson questioned Rentschler as he walked through a PowerPoint with his analysis of the case. When asked about his opinion on whether abrasions on O’Keefe’s arm were consistent with striking the right-rear taillight of Read’s SUV, he said they were “inconsistent." He counted 36 different injuries on O’Keefe’s arm and said that would mean the taillight would have had to have hit him in 36 different spots.

Rentschler gave his thoughts on a paint test conducted by one of the prosecution’s crash reconstructionist experts: Aperture’s Dr. Judson Welcher. Dr. Welcher concluded that O’Keefe’s injuries were consistent with a vehicle collision based on his testing. Rentschler said Aperture’s test was “inconsistent” with the kinematics of the scenario of O’Keefe’s right arm hitting the SUV, being propelled backwards 7 to 10 feet, and falling straight back onto a hard surface.

Defense Finishes Questioning

Jackson finished his questioning by asking Rentschler if he believed, based on the biomechanical evidence, O’Keefe could have sustained his head injuries from being hit by Read’s SUV and falling into the yard.

“My opinion is that the evidence is inconsistent with Mr. O’Keefe being struck on the right arm by the SUV, then moving laterally into the yard and falling backward onto the back of his head,” said Rentschler.

Cross-Examination, Re-Cross-Examination

Special prosecutor Hank Brennan handled cross-examination for the prosecution, immediately grilling Rentschler on his relationship with the defense. There were concerns raised after it was discovered the defense had paid ARCCA for testimony, despite Rentschler and fellow ARCCA witness Dr. Daniel Wolfe being represented as independent from either side. The ARCCA witnesses were initially hired by federal investigators and Judge Beverly Cannone ruled they were allowed to testify again in the retrial.

Brennan asked Rentschler if he had received information during the trial that could have impacted his testing and opinion. He said he was given some evidence by his employer but said it didn’t make a difference for his analysis and conclusions. Several times, Brennan started by saying “facts matter” before asking his question. The defense objected numerous times and many were sustained by Judge Cannone, leading to sidebars.

Brennan also questioned Rentschler about what happened after he testified in the first trial, to which he responded that he had lunch before heading to the airport. He said he ate a ham sandwich in the room that the defense was also in, but did not remember what conversations he had before he was picked up.

When asked about ARCCA billing the defense team, Rentschler said he was unaware if they had paid it or not and that he is not involved with billing. He also testified that he is a salaried employee and had not received any money from the defense for being involved with the case.

Just before the lunch break, Brennan started trying to cast doubt on Rentschler’s testing, analysis, and conclusions on the broken taillight evidence. Earlier in cross-examination, Brennan pointed out that Rentschler had "no idea" where the collision point was in the alleged crash. Rentschler responded that "nobody does."

When the jury returned from the break, Brennan went back to Rentschler's earlier testimony comparing his tests to Dr. Welcher. Rentschler testified that if Welcher did not recreate how O'Keefe was positioned, the speed of impact, how his body moved, or where he ended up, then he "did not conduct either an accident reconstruction analysis or a biomechanical causation of the analysis."

Defense Rests Its Case

Following further redirect and re-cross-examination questioning, Jackson said the defense rested its case.

Jurors Excused, Closing Arguments Friday

After jurors were sent home for the day, Judge Beverly Cannone said she was taking a 10-miniute break to review a matter then would return for a discussion with the court. The judge then heard arguments about evidence from the prosecution and defense. And the prosecution said it would not be calling any witnesses in rebuttal.

Jurors were not be in court on Thursday while a charge conference was held to discuss jury instructions. Closing arguments will be on Friday, and the judge wants the jury to get the case by Friday afternoon.

NightSide with Dan Rea