(NewsNation) — Jurors failed to reach a verdict in Karen Read’s Massachusetts trial on charges alleging she killed her boyfriend by hitting him with an SUV, leading the judge to declare a mistrial Monday.

The announcement came after nearly 26 hours of deliberation and multiple attempts to avoid a hung jury. The jury first told Judge Beverly Cannone on Friday that they couldn’t reach a unanimous verdict. Friday marked the fourth day of deliberations.

Read’s attorneys said the jury already had enough time, but Cannone told jurors to keep deliberating.

What happens in a mistrial?

The judge declared a mistrial after instructing the jury to continue deliberating, but three times, the jurors said they were unable to reach a unanimous verdict.

A mistrial resulting from a hung jury could lead to a new trial as prosecutors want to bring the case forward again. A judge could rule against a retrial under certain circumstances, but often, prosecutors can proceed, according to the Fully Informed Jury Association (FIJA).   

Meanwhile, Read won’t be convicted or acquitted of the charges since the jury never reached a verdict indicating one or the other. Any bond conditions that were effective before the trial could be reinstated.

Is a deadlocked jury better or worse for a defendant?

From a tactical standpoint, a hung jury can fare better for the person on trial than a conviction, according to FIJA. That’s because there are more barriers to appealing a conviction, including mounting legal costs. People who appeal a conviction also aren’t presumed innocent like they are before a trial.

What is Karen Read charged with?

Read, 45, from Massachusetts, is accused of killing her boyfriend, 46-year-old Boston police officer John O’Keefe.

Prosecutors allege Read hit O’Keefe with an SUV and took off during a 2022 snowstorm. She’s pleaded not guilty to the felony charges, which include second-degree murder, vehicular manslaughter while intoxicated and leaving the scene of a collision causing injury or death.

A second-degree murder conviction could result in life in prison.

What did jurors learn at trial?

O’Keefe was found unresponsive in a snowbank outside of a fellow police officer’s home in suburban Boston. He was pronounced dead at a local hospital after suffering from hypothermia and a head injury, according to police.

Prosecutors said Read and O’Keefe were together at two different bars drinking before she dropped him off. That’s when investigators say Read hit O’Keefe with her car while making a three-point turn. She then drove off, prosecutors said.

Prosecutors showed evidence to suggest that O’Keefe asked her friends whether she could have hit O’Keefe with her vehicle.

They also said she struck him intentionally, suggesting the relationship soured in the month leading up to O’Keefe’s death.

Read’s attorneys, however, said she was the victim of a police cover-up — an argument prosecutors have denied. Read told ABC News she “never harmed a hair on John O’Keefe’s head.”

A turning point in the case came when State Trooper Michael Proctor, the lead investigator on the case, took the stand. He acknowledged sending offensive texts about Read to friends, family and fellow troopers during the investigation. He apologized for the language he used but insisted they had no influence on the investigation.

On Monday, Massachusetts State Police relieved Proctor of duty and transferred him, saying the move followed the agency’s previous decision to open an internal affairs investigation after getting information about potential serious misconduct.

Retired DEA Supervisory Special Agent Sean McDonough told NewsNation host Brian Entin the decision was “long overdue.”

“The state police should have done this action well before this ever came to trial. They knew what was in his personal cellphone,” McDonough said on “Banfield.” “This case should have never come to trial, and they were warned to not bring this case to trial.”