And with enough legal expertise—and financial resources—defendants can line up parades of experts to try to undermine a prosecution witness’s interpretation of forensic data, from the timing of a Google search to the movement of a human body.

“With technology advancing at such a rapid pace, the things we used to think were black and white are no longer black and white,” said Christina Miller, a professor at Suffolk Law who previously focused on cases involving digital forensics as a Suffolk County prosecutor.

She noted two recent Massachusetts Supreme Judicial Court rulings that each upheld decisions not to allow certain data to be used as evidence because of questions about its accuracy: In 2021, courts allowed the calculation of a defendant’s speed with a GPS device, and earlier this year , the courts prevented evidence of a defendant’s cell phone location history from being introduced in a criminal trial.

In the latter case, the prosecutor’s analysts had used a different version of an iPhone’s operating system when trying to replicate the data. It underscored one of Miller’s main points: “The forensic examiner is only as good as the tools they use, and the tools are only as good as the data.”

Expect to see more court challenges, she said.

Michael Kendall, a former federal prosecutor who is now a defense attorney, added that judges need to be “much more demanding” in determining the validity and credibility of someone claiming to be an expert — as well as what science and processes are sufficiently rigorous to constitute salient evidence.

“There has been so much bogus scientific evidence that has misled people over the years,” he said. “There has to be some validation of the expert. The court has to check the quality of the experts and the quality of the science.”

The reliability of some digital forensic data varies with the type of technology in question. Programs were developed to complete specific functions, not to serve, for example, as an official time-stamped record of events that could constitute irrefutable evidence, said Seth P. Berman, a defense attorney and former prosecutor. So even though emails, Google searches, or phone calls may contain a timestamp, that doesn’t mean the timestamp itself is accurate.

“This whole area of ​​computer forensics is basically an accident,” said Berman, who heads the privacy and data security practice group at the Nutter law firm and previously worked for a firm specializing in digital forensics. “No one created computers with the goal of using them to create evidence.”

So, he added, “As a result, the data is not that clear. There are a lot of things that just go wrong,” and can lead to different expert interpretations.

Take, for example, the case of Read. She was accused of rear-ending her boyfriend, Boston police officer John O’Keefe, with her Lexus SUV after a night of heavy drinking in 2022 and left him to die outside the Canton home of another Boston police officer during a snowstorm. Her defense team claims she is being framed and that O’Keefe was actually beaten by people who had attended a gathering inside the home and then dumped outside. Read found O’Keefe’s body hours later in a snowbank, after returning to look for him.

The case ended in a mistrial in July and a new trial is scheduled for January.

At the heart of the defense’s theory is the timing of a Google search for “hos (sic) long to die in cold” by Jen McCabe, a woman who was at the gathering inside the Canton home. According to an expert hired by the defense, records show she Googled the request on her phone at 2:27 a.m., hours before O’Keefe’s body was found. Many among the throngs of Read supporters who regularly gathered outside the courthouse cited the testimony as a conclusive indicator of her innocence.

But prosecution experts said the testimony was incorrect and that the search took place after Read and McCabe found O’Keefe’s body shortly after 6am. The discrepancy, prosecution witnesses said, was due to confusion about what the time stamp referred to; they said the 02:27 stamp only referred to when web page that was later used for the search was opened first.

There were similar ones different claims over other evidence: calls that were deleted from the phone, or not; how fast Read’s car accelerated in reverse; O’Keefe’s movements, based on data from his phone and watch.

Read’s team of lawyers mounted an aggressive defense, sharply cross-examining most of the government’s witnesses and even producing some of their own.

A judge declared a mistrial after the jury reported deadlocked and unable to reach a verdict. Read maintains his innocence.

Berman noted that most defendants do not have the financial resources of Read, a financial analyst and adjunct professor who also benefited from donations from ardent supporters. A defense effort that had less time, manpower and money likely wouldn’t have been able to push back as forcefully on data inconsistencies, he said.

Ultimately, it is judges who determine the credibility of an expert witness or the validity of a piece of science, guided by decisions of appellate courts, including US Supreme Court precedent. The goal is to “win science from junk science,” said Rosanna Cavallaro, a Suffolk law professor who teaches evidence. But that can be difficult, she said, as new technologies and expertise in those technologies develop.

Cavallaro also said that a “battle of the experts” can be detrimental to a case when the process involves each side simply looking for the most beneficial expert they can find — someone who will not only reach the conclusion they seek, but who will communicate the engaging and effective.

Sometimes, she said, “you worry that the person’s opinion is for sale. The problem has been consistent across science.”

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Sean Cotter can be reached at [email protected]. Follow him @cotterreporter.