Retired forensic pathologist Dr. Frank Sheridan (not shown) is questioned by defense attorney Elizabeth Little during the murder trial for Karen Read on Monday at Norfolk Superior Court, in Dedham, Mass. Pat Greenhouse/The Boston Globe via AP

DEDHAM, Mass. — Jurors in the long-running murder trial of Karen Read must decide whether she was a callous girlfriend who drove off after running over her Boston police officer boyfriend with her luxury SUV, or whether police framed her to cover up a brutal beatdown by his fellow officers.

After nearly two months of testimony and a media storm fanned by true crime bloggers, lawyers were due to deliver closing arguments Tuesday before jurors tasked with sifting the wildly differing accounts of the death of Boston Police Officer John O’Keefe.

Prosecutors contend Read struck O’Keefe with her Lexus SUV in January 2022, leaving him unconscious outside in the snow after a night of bar hopping. He died in a hospital after being found unresponsive hours later outside the Canton home of another Boston police officer who had hosted a party. The cause of death was hypothermia and blunt force trauma, a medical examiner testified.

Arguing that Read was framed, her lawyers contend O’Keefe was dragged outside after he was beaten up in the basement of fellow officer Brian Albert’s home in Canton and bitten by Albert’s dog.

Read, a former adjunct professor at Bentley College, is charged with second-degree murder, manslaughter while operating under the influence of alcohol, and leaving the scene of personal injury and death.

On Monday, three witnesses for the defense cast doubt on the prosecutors’ version of events.

Dr. Frank Sheridan, a retired forensic pathologist and former chief medical examiner for San Bernardino County in California, testified that O’Keefe should have had more bruising if he’d been struck by the SUV. He also suggested that scratch marks on O’Keefe’s arm could’ve come from a dog and that other injuries were consistent with an altercation.

Two witnesses from an independent consulting firm that conducts forensic engineering also suggested some of the evidence didn’t line up with the prosecution version of events. Describing their detailed reconstructions, the witnesses said they concluded that damage to Read’s SUV, including a broken taillight, didn’t match with O’Keefe’s injuries.

“You can’t deny the science and the physics,” Andrew Rentschler from the firm ARCCA said at one point, describing an analysis of the level of injuries associated with various speeds of a vehicle like Read’s. ARCCA was hired by the U.S. Department of Justice as part of a federal investigation into state law enforcement’s handling of the Read case.

The defense contends investigators focused on Read because she was a “convenient outsider” who saved them from having to consider other suspects, including Albert and other law enforcement officers who were at the party.

Testimony began on April 29 after several days of jury selection. Prosecutors spent most of the trial methodically presenting evidence from the scene. The defense called only a handful of witnesses but used its time in cross-examining prosecution witnesses to raise questions about the investigation, including what it described as conflicts of interest and sloppy police work. The defense was echoed by complaints from a chorus of supporters that often camp outside the courthouse.