New evidence is emerging in the case of a Boston police officer who died in a snowbank last year, apparently after being struck by his girlfriend's car in Canton. Authorities charged the girlfriend, Karen Read, with several crimes surrounding the death of Officer John O'Keefe, including manslaughter. But according to the defense, there is new evidence that casts doubt on Read's involvement and instead points to a different and potentially alarming theory of O'Keefe's death. GBH's legal analyst and Northeastern law professor Daniel Medwed joined Morning Edition host Jeremy Siegel to discuss. This transcript has been lightly edited.

Jeremy Siegel: So let's start with the facts, what we really know about this case. What exactly do we know happened? What do we know about how John O'Keefe died?

Daniel Medwed: Well, a lot of the things we thought we knew maybe have changed. We're not so sure. But here's what we do know: O'Keefe died after being left out in the elements during a terrible blizzard back in January 2022. Evidently, he'd gone drinking with his girlfriend, Karen Read to a couple of bars. And Read dropped him off outside a house party in Canton. It was a home that belonged to another Boston police officer, a man named Brian Albert. So, Read left. She went home, and then she realized several hours later, Hey, I haven't heard from O'Keefe. I haven't heard from my boyfriend. So she went back to the place where she had dropped him off and found him in tremendous distress. He was bleeding profusely, had a lot of injuries. She called 911. He was taken to the hospital, where he was pronounced dead. And the medical examiner determined that he had suffered from hypothermia and multiple skull fractures.

Siegel: So I mentioned earlier that Read ended up being charged with several crimes, including manslaughter surrounding the death. How did Karen Read end up becoming a suspect in the first place? What was the initial police theory surrounding the case?

"A lot of the things we thought we knew maybe have changed."
-Daniel Medwed, GBH Legal Analyst

Medwed: So the police hypothesized that Read had inadvertently struck O'Keefe with her car when she did a three-point turn to leave the scene where she had dropped him off, and that she struck him, didn't look back to see if anything had happened and then went home. Again, the theory was essentially recklessness or negligence, not intent. That was the theory. Now, to be fair, some of the circumstantial and direct evidence did point to her involvement. First, she had a broken tail light when she came back to pick him up or to find him. And she couldn't explain when or where that had it had been broken. And second, she made several inculpatory statements: She told her friend, 'Did I hit him? Could I have hit him?' And she made similar statements even more emphatically to a Canton firefighter.

So ultimately, prosecutors charged her with three crimes: Manslaughter, motor vehicular homicide and the crime of leaving the scene of a collision that caused a death. Again, I need to emphasize that the theory here, the operating assumption, was recklessness, that she consciously disregarded a risk by doing that three-point turn during blizzard like conditions and not looking back.

Siegel: Daniel, what do we know about this new evidence that the defense claims to have found?

Medwed: So over the course of the past few weeks, Read's defense team has come forward and alleged the existence of some new evidence that could create an entirely different vision of the facts that led to O'Keefe's death. So for one thing, the defense claims that it has conducted a forensic analysis of O'Keefe's cell phone, which, again, according to the defense, suggests that O'Keefe went inside the Albert residence, that at some point he went inside, which undermines or undercuts the theory that he was struck and left in the snow bank and never made it into the home. In addition, the defense also claims to have done a forensic analysis of the cell phone of one of the partygoers, the sister-in-law of the homeowner, Brian Albert. And they maintain that the sister-in-law had done a Google search on her phone to the effect of 'How long to die in the snow,' and then she took steps to cover up that search history and to delete several text messages before turning her phone over to law enforcement.

And finally, the defense maintains that many of O'Keefe's injuries are inconsistent with those that someone would suffer if they were just struck by a car. The upshot is they're suggesting that maybe the cause of death here is very different, and that Karen Read may not be responsible.

Siegel: So this is a lot, and a lot of it upending in many ways what we assume to be the case surrounding this. Is there any way to know the credibility of this at this point?

Medwed: You know, at this point, I think it's premature. That's really what trial is all about, to vet the evidence in open court through the crucible of cross-examination, which is called the greatest legal engine ever devised for the discovery of the truth. I love that phrase. I tell my students that all all the time.

But we do know that the Norfolk County District attorney's office seems pretty skeptical. They issued a very terse and cursory press release that said to the effect that they are somewhat dubious about how the defense has interpreted the raw data from the cell phones, and that they plan to have a response around May 3 or shortly thereafter, when there's the next court appearance.

Siegel: So we'll find out more soon. But let's assume that there is something to this defense, that it is credible. What would end up happening next?

Medwed: Well, if the prosecution determines that it is quite credible and quite meaningful, in theory, they could drop the charges against Karen Read and investigate the case further, potentially looking into the involvement of some of the partygoers. But if the prosecution determines that it isn't very sizable, that it isn't meaningful evidence, then it could decide to go to trial and let the chips fall where they may. So I think we just have to stay tuned and see what happens here.

Siegel: Have you seen something like this happen before? Is it normal for a case that's this high-profile, that involves the police, for new evidence to potentially be coming in at this stage, after the charges are already filed, that totally upends what we might be thinking about the case?

Medwed: It doesn't happen all that often, but it does happen from time to time. It is a somewhat unusual moment pretrial for it to emerge, you know, over a year later. I mean, this incident happened in January 2022. So it is a little interesting in terms of its timing. But it's not unprecedented in my experience.