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The Karen Read murder trial highlights a fascinating legal rule

Read’s legal team will be heavily relying on expert witnesses to try to convince the jury of her innocence.
Karen Read seated at her pre-trial hearing at Norfolk Superior Court, in Dedham, Mass.
Karen Read at Norfolk Superior Court, in Dedham, Mass., on April 12.David L. Ryan / Boston Globe via Getty Images file

The prosecution has now rested in the trial of Karen Read, a Massachusetts woman accused, among other things, of killing her boyfriend in 2022. She has pleaded not guilty, and her defense argues that she was framed.

The details of the case have been riveting from the start. In June of 2022, a grand jury in Massachusetts returned an indictment against Read for multiple charges, including the second-degree murder of her boyfriend, Officer John O’Keefe. A 16-year veteran of the Boston Police Department, O’Keefe was found unresponsive in the early morning hours of Jan. 29, 2022, on the lawn of the home of Brian Albert, a fellow police officer. According to the first responders, at the time “there was an active blizzard occurring with heavy snow and the temperature in the teens.” O’Keefe was pronounced dead shortly thereafter at the hospital.

The defense claims that Read is being framed by law enforcement and others.

O’Keefe’s body showed signs of trauma and the medical examiner’s opinion as to cause of death was blunt force trauma and hypothermia. The prosecution has accused Read, O’Keefe’s girlfriend of two years, of driving her Lexus SUV while she was under the influence and intentionally backing into and striking O’Keefe, leaving him to die in the cold outside of his colleague’s home. The defense claims that Read is being framed by law enforcement and others, and that O’Keefe was actually beaten inside of Albert’s house, bitten by Albert’s dog, and then left outside the home. The defense has also raised issues over the lead investigator, Massachusetts State Trooper Michael Proctor, who is the subject of an open internal affairs investigation and who admitted on cross-examination to sending inappropriate and vulgar texts about Read.

Now that the prosecution has rested, it’s time for the defense to present its case-in-chief, and Read’s legal team will be heavily relying on expert witnesses to convince the jury of her innocence. Earlier this week, the presiding judge, Beverly Cannone, spent the entire day Tuesday allowing the lawyers to voir dire three of the defense’s proposed expert witnesses.

You may think that voir dire is limited to just the jury selection process, but it can also apply to the vetting of prospective expert witnesses. And in the context of possible trial witnesses, voir dire is a vehicle by which lawyers can question these individuals to vet whether they meet the appropriate qualifications and evidentiary threshold to be able to testify.

Pursuant to Rule 702 of the Federal Rules of Evidence, lawyers can challenge a proposed expert witness on the basis of their “knowledge, skill, experience, training, or education.” They can also challenge the underlying methodology by which the expert reached their opinion in the case, and also whether the expert’s testimony would “help the trier of fact to understand the evidence or to determine a fact in issue.” Let’s remember what an expert witness is really there to do in a trial: to explain a complex issue in a way that helps the jurors to accomplish their ultimate fact-finding mission.

In Read’s case, the prosecution sought to exclude three of her listed expert witnesses to prevent them from being able to testify in her defense. Without the jury being present, Judge Beverly Cannone allowed the prosecution to question these witnesses on Tuesday at length. Then, the judge announced her ruling: Dr. Marie Russell, a retired emergency room physician and forensic pathologist, can testify that in her expert opinion, O’Keefe’s arm injuries were consistent with a dog attack. However, the judge made it clear that Russell cannot testify about police activity or what the injuries are inconsistent with.  

Dr. Daniel Wolfe, an accident reconstruction expert, can also testify as to whether the damage to Read’s SUV and O’Keefe’s injuries are consistent with a pedestrian collision. Interestingly, Wolfe’s company was not hired by the defense, but by a “third-party agency.” Wolfe testified that the information that he was provided to analyze in order to render an expert opinion was given to him by the Department of Justice and the FBI. (Earlier this year, the existence of a pending investigation by the U.S. Attorney’s Office for the District of Massachusetts into Read’s arrest and prosecution was revealed.)

Judge Cannone reserved ruling on Dr. Andrew Rentschler, who is a biomechanical engineer and also an accident reconstructionist, and who was not hired by the defense or the prosecution. He was tasked to determine whether O’Keefe’s injuries to his head and arm were consistent with contact with Read’s Lexus SUV. Judge Cannone explained her ruling: “It’s clear to me that in Massachusetts, biomechanical engineers are not qualified to testify as to medical causation of an injury. Only an MD can do that…So I’m going to reserve ruling on the rest of his testimony. There are certain things he can testify, and I’ll hear from [Read’s defense] again before he testifies next week.”

The court was able to make these rulings in terms of the admissibility, scope and use of these expert witnesses because of the voir dire process that occurred. It’s important to note that experts cannot testify as to the guilt (or innocence) of a criminal defendant. They cannot provide a direct opinion as to whether the defendant committed the crime or not. In fact, Rule 704 explicitly states that: “In a criminal case, an expert witness must not state an opinion about whether the defendant did or did not have a mental state or condition that constitutes an element of the crime charged or of a defense. Those matters are for the trier of fact alone.”

It’s not just the defense that has deployed an expert witness. Last month, the prosecution called its own expert to refute the defense’s claim that O’Keefe’s arm injuries were caused by a dog attack. Trials sometimes devolve into a “battle of the experts.” And in Karen Read’s case, her fate may ultimately depend on whether and how much the jury believes her expert witnesses.