Here's what could happen next for Karen Read after mistrial

BOSTON -- The murder trial of Karen Read ended in a mistrial Monday after jurors couldn't reach a unanimous verdict, prolonging a case that's divided a Massachusetts community amid allegations of a sweeping cover-up by police and investigative misconduct.

While not an acquittal, the outcome was a boon for Read, who is accused of drunkenly driving into her then-boyfriend, Boston police officer John O'Keefe, and leaving him to die on a snowy night in January 2022 outside a home in Canton, Massachusetts. The 45-year-old had pleaded not guilty to charges of second-degree murder, vehicular manslaughter while intoxicated and leaving the scene of a collision, and she faced up to life in prison if convicted.

RELATED: Things to know about the Karen Read murder case, which has ended in a mistrial

But prosecutors with the Norfolk District Attorney's Office failed to convince the jury of six men and six women beyond a reasonable doubt. Over the last two days of the five-day deliberations, jurors repeatedly informed the judge they were hopelessly deadlocked, saying in a final note on Monday their perspectives were "starkly divided."

Now, prosecutors must decide whether to rethink their approach. As they reconsider their case, they may decide to present evidence differently in hopes of securing a conviction, or avoid a second trial altogether and offer a plea deal, legal experts said.

"They're going to make an assessment about basically what went wrong," trial attorney Misty Marris told CNN. "You go back, and you do the diagnostic: Where does the evidence fail to meet those standards from the jury's perspective?"

Here's what could happen next:

Prosecutors intend to retry the case

In a brief statement Monday, the office of Norfolk County District Attorney Michael Morrissey said it plans to retry the case, which alleged Read and O'Keefe had gotten into an argument the night of January 28, 2022, before she struck him with her SUV and fled the scene.

The couple had been out drinking at two bars with friends, then went to the home of O'Keefe's colleague for an after-party, court documents show. O'Keefe was found the next morning bruised and battered in the snow outside the home in Canton.

Read and her attorneys had, in turn, presented another theory: Read dropped O'Keefe off, then left - while O'Keefe was injured in a fight with off-duty officers inside the home, mauled by the homeowners' dog, then tossed in the snow to die. The police then conspired to fabricate evidence and lie under oath to protect their own and frame Read, her defense alleged.

Court documents say Read went looking the next morning for O'Keefe in the snowstorm and found his body in the front yard of the Canton home.

Prosecutors rejected that theory, presenting evidence the couple had a volatile relationship. Firefighters who responded the morning of January 29 to the site of O'Keefe's body asked about his injuries and were told by Read, "I hit him, I hit him," according to their testimony. Additionally, Read's vehicle had a broken taillight, and pieces of the taillight were found at the scene.

Read's attorneys on Monday signaled they would not shy away from a retrial.

"No matter how long it takes, no matter how long they keep trying, we will not stop fighting. We have no quit," Alan Jackson, one of Karen Read's attorneys, said in video provided by CNN affiliate WCVB outside the courthouse.

Prosecutors could rethink the case ...

Prosecutors' decision to quickly signal their intent to retry the case wasn't unexpected, said Rosanna Cavallaro, a professor of law at Suffolk University in Boston.

"They don't want to be seen as thinking that they failed, or that they have nothing but a very strong case," she said. "But the reality is, of course, that what a mistrial means is that the jury could not agree, and they were not persuaded."

But ahead of a status conference on July 22, prosecutors will be engaged in a post mortem of the case, said Daniel Medwed, a law professor at Northeastern University, and they will be asking themselves a series of questions.

"What worked, what didn't work? If they were to proceed again," he said, "would they choose the same charges? ... Would they change their strategy in some ways? Where are places that they need to shore up their case, maybe through additional investigation?"

Perhaps, Medwed said, prosecutors will look back and feel they overreached charging Read with murder, which requires intent, and instead focus on the other charge. "They might just consider dropping the murder charge and going with manslaughter," he said.

Indeed, Cavallaro said the indictment against Read and the charges stemming from it would not change. But prosecutors could offer another narrative that would make it easier for a second jury to convict Read on a lesser type of homicide than second-degree murder like manslaughter or reckless manslaughter.

The stories heard by the jury were "binary" and "polarized," she said: In prosecutors' telling, Read intended to kill O'Keefe, while the defense argued she was innocent and framed. "It's possible the second time around, the government says, 'Maybe we need to give the jury this intermediate possibility that she didn't mean to kill him,'" Cavallaro said, in addition to alleging Read intended to murder O'Keefe.

"It captures the idea that a reasonable person would have been more careful, and because of your lack of care, your recklessness, a death occurred that you're responsible for," she added.

"That behavior is punishable as a homicide, but not as a murder," she said.

... or offer a plea deal

Former Massachusetts Attorney General Martha Coakley indicated in an interview with WCVB that prosecutors could drop the most serious charge of second-degree murder, adding, "They can also seek to plea bargain, which is something that I'm guessing they will at least talk about."

"If I were defense counsel, you owe it to your client to talk and the prosecution could talk about whether they could reduce charges and reach some plea agreement," Coakley said.

In jurors' final note to the judge before she declared a mistrial, they said "some members" believed the prosecutors had met the burden of proof, proving the charges beyond a reasonable doubt. But "others" felt the evidence failed to meet that standard.

Jurors' language signaled it was not a single holdout but multiple jurors who were unconvinced, Cavallaro said, which the defense would take as a win. "Given that," she asked, "is there any temptation for (Read) to plead?"

Medwed echoed that idea, pointing out that Read's defense focused on her proclaimed innocence in O'Keefe's death. He would be surprised if she was interested in pleading guilty to anything that would include admitting she caused O'Keefe's death.

State trooper's testimony appears to be key

A key decision could be whether to present testimony from a lead investigator who had to apologize on the stand for sexist and offensive texts he sent about Read in a private group chat, according to WCVB. Massachusetts State Police Trooper Michael Proctor called her a "whack job," mocked her medical issues and told coworkers he found "no nudes" while searching her phone for evidence, the station reported.

Proctor was relieved of duty Monday following the mistrial, state police Col. John Mawn said in a news release.

"This follows our previous decision to open an internal affairs investigation after information about serious misconduct emerged in testimony at the trial," Mawn said, adding the investigation is ongoing.

CNN has sought comment from the State Police Association of Massachusetts. An attorney for Proctor previously said he was cooperating with the internal inquiry and said his personal messages did not undermine the investigation into O'Keefe's death.

There's no evidence Proctor tampered with any evidence, Julie Grant, a Court TV anchor and a former federal prosecutor, told CNN's Sara Sidner Tuesday. But his behavior and comments were "unprofessional."

"The Massachusetts State Police - you have to wonder if they felt as if he had any role in this hung jury," she said.

Still, experts who spoke to CNN saw Proctor's testimony as key to the commonwealth's case, which might force prosecutors to call on him despite the apparent baggage.

"He's the lead investigator, which means that his performance, his work, his efforts are inherently relevant to the case," Medwed said, adding the defense would likely call the trooper to impeach the investigation even if prosecutors didn't.

"I just don't see how the government can avoid him as much as they'd like to," Medwed said.

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