It is finally showtime for the court case surrounding the death of Boston police officer John O'Keefe in January 2022. 

The trial has started for his then-girlfriend, Karen Read, who is accused of intentionally backing her Lexus SUV into O'Keefe after a drunken fight in the car and leaving him to die in the snow outside a fellow officer's home, according to prosecutors. 

Not only has Read pleaded not guilty to murder, her legal team argued Read was framed by people in the Canton, Massachusetts, home, as part of a top-to-bottom cover-up.

Those allegations are part of an ongoing federal investigation, which fueled the "Free Karen Read" side of a fiercely divided Boston suburb. Then came the October arrest of a controversial local blogger, who led rallies supporting Read.

Karen Reads sits in court

Karen Read in court with her attorney, David Yannetti. (Matt Stone/MediaNews Group/Boston Herald via Getty Images)

KAREN READ, CHARGED WITH MURDER IN BOSTON COP BOYFRIEND'S DEATH, LEARNS TRIAL START DATE AFTER HEATED HEARING

Videos and photos of Aiden Kearney, who is better known as "Turtleboy," in handcuffs for allegedly intimidating witnesses was the lighter that lit a river of gasoline. 

His blog's loyal followers – who call themselves "Turtle Riders" – came out in full support of Kearney, as his lawyers told the judge his client "vehemently denies" the accusations and argued his opinions are protected by the First Amendment

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Karen Read kisses O'Keefe

Karen A. Read, girlfriend of the late Boston Police officer John O'Keefe, was arraigned in Norfolk Superior Court on charges of second-degree murder in his death in Dedham, Massachusetts, on June 10, 2022. A photo of the couple together was presented by the defense to the prosecution. (John Tlumacki/The Boston Globe via Getty Images)

Read's high-powered defense team, including Alan Jackson, who helped Kevin Spacey get acquitted on sexual assault charges in 2019, said in court documents the investigation was "sloppy" and concealed a complex web of personal and romantic relationships.

Those alleged relationships were detailed at length in court documents. 

Boston Police Officer John O'Keefe

Authorities discovered John O'Keefe outside a Canton, Massachusetts, home on the morning of Jan. 29, 2022. (Boston Police Department)

The trial started with the jury selection on Tuesday, and "We're looking forward to bringing the evidence to the grand jury," the prosecutor's office said. 

Here are three things to know about Read's murder case.

1. O'Keefe found dead in snow

O'Keefe was 46 when he went out with his friends during the overnight hours from Jan. 28 to 29, 2022, but he never came home. 

His body was found in the snow outside retired Boston police officer Brian Albert's Canton, Massachusetts, home around 6 a.m.

Read, a now-45-year-old financial analyst and college professor, was dating O'Keefe at the time. She said she dropped him off at Albert's home around 12:30 a.m.

She said O'Keefe never came home, and he could not be reached. Read and her friends went out for him, when Read said they found O'Keefe's body in the snow outside the suburban home.

Karen Read supporters outside courthouse

Hundreds of Karen Read supporters gather in front of Norfolk County Superior Court before one of her appearances. (Matt Stone/MediaNews Group/Boston Herald via Getty Images)

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Prosecutors allege Read was drunk, argued with O'Keefe and ran him over with her car when she dropped him off. 

Her defense team has argued O'Keefe went inside the home, was killed during a fight and someone dragged his body outside.

His injuries were caused by Albert's dog, according to Read's lawyers, or by Read's car, according to prosecutors. 

Read was arrested on Feb. 2, 2022 and charged with second-degree murder, manslaughter while operating under the influence of alcohol and leaving the scene of an accident, causing injury and death. She pleaded not guilty to all charges.

"I did not kill John O’Keefe. I have never harmed a hair on John O’Keefe’s head," Read told ABC News last August.

Kared Read leaves court with attorneys

Karen Read and her attorney, Alan Jackson, after a court appearance. (Matt Stone/MediaNews Group/Boston Herald via Getty Images)

2. Read alleges cover-up

A murder case splintered into a federal probe after Read's lawyers laid out allegations of a cover-up to protect Albert, whose family lived in Canton for generations. Locals say the family has enormous influence and connections. 

That included Massachusetts State Trooper Michael Proctor, who was the lead investigator on the case, according to Read's lawyers, who said Proctor allegedly hid those personal ties. 

Proctor, through a lawyer, and the state police have each denied these allegations, and Proctor has remained on active duty. 

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Albert's supposed connections reached into Norfolk County, including District Attorney Michael Morrissey, whose office is prosecuting the case, as well as the Boston Police Department. Morrissey and Albert have denied any wrongdoing. 

Despite everyone claiming innocence, a federal investigation continues, even as Read's trial begins, which boggled the mind of a source close to the case who told The New York Post, "I've never seen anything like this before."

"It’s pretty crazy and yet the Norfolk DA is going ahead with the trial and no one’s stopping it," the unnamed source told The Post. "To me the [prosecutors] are on a suicide mission."

WATCH: MORRISSEY VIDEO STATEMENT ON READ'S CASE

3. Lightning rod blogger fuels tale of two towns

As if the case was not wild and divisive enough, enter "Turtleboy's" at-times aggressive activism. 

Kearney, who goes by the nickname and covers such cases for his blog, led several rallies and fueled the "Free Karen" side of the debate. 

He is often seen with a cellphone camera and bullhorn leading demonstrations and trumpeting Read's law enforcement cover-up defense.

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The Norfolk County District Attorney's Office alleged he crossed the line by intimidating witnesses and was arrested in October, which enraged his loyal followers. 

The prosecutor alleged Kearney "showed up" at sporting events of witnesses' children and "made scenes," harassed and photographed witnesses at their homes and jobs and instructed followers of his blog to do the same.

Massachusetts blogger Turtleboy Aiden Kearney

Massachusetts blogger Aiden "Turtleboy" Kearney was charged with witness intimidation for allegedly threatening witnesses in a murder case in Massachusetts. (Aidan Kearney(@DoctorTurleboy)/X)

His lawyer told the judge his client "vehemently denies" the accusations when Kearney pleaded not guilty, saying his client's opinions are protected by the First Amendment

Kearney told Fox News Digital in an X message after his arrest and subsequent release on bond that, "It speaks volumes that instead of looking to find John O'Keefe's murderer, these detectives, who are close family friends of the Alberts, dedicated time and resources to charging me with witness intimidation for asking the questions that they won’t.

"It’s a sad day for America when our police force is weaponized against journalists in order to protect cop killers."

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Kearney was indicted on over a dozen felonies involving witness intimidation. He also served 60 days in jail for violating a protective order, but he has since been freed and is waiting for his own trial.

Two years have elapsed since Read was indicted by a grand jury, and it is finally time for a jury to decide if O'Keefe's death was a domestic violence murder or consider whether it might have been part of an elaborate cover-up orchestrated by law enforcement and prosecutors.

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The curtains opened with jury selection, which a local law professor said will be pivotal and challenging.

"The influence of media, social media, the sidebars with the turtle blogger. All the information that's been going back and forth from the DA's office and the defense team, I think it's going to be a long road to pick an impartial jury," Suffolk University Law Professor Christopher Dearborn told CBS News.