Karen Read is at the center of a new documentary series offering intimate access as she and her legal team gear up for her retrial in the death of her boyfriend, Boston police officer John O'Keefe -- and TMZ has your exclusive first look at Tuesday's upcoming episode.

In Investigation Discovery’s "A Body in the Snow: The Trial of Karen Read," Karen opens up her Mansfield, Massachusetts home to cameras and questions, insisting the allegations against her don’t add up.

Prosecutors allege in 2022, Read got into a heated drunken argument with O’Keefe before backing up and hitting him with her SUV, killing him ... then fleeing the scene, leaving him to die in a friend's snow-covered front yard.

Read has always insisted she's innocent, and her team claims she was framed -- saying John got into a fight with his fellow officers that night and they pinned his death on her.

Karen’s first trial ended in a mistrial last year ... the jury voted to acquit her on second-degree murder and fleeing the scene -- but deadlocked 9-3 in favor of convicting her on vehicular manslaughter.

The new docuseries dives into Karen’s upcoming April retrial, the investigation, her preparations, and the surrounding theories -- featuring key figures and an inside look at her mindset during 2024's trial. Read's facing charges of second-degree murder, motor vehicle manslaughter while driving under the influence, and leaving the scene of a collision causing death.