Here's a rundown of what's going on...

People of Note:
John O'Keefe - The deceased, a Boston police officer
Karen Read - The accused, girlfriend of John O'Keefe
Brian Albert - Owner of the home where a party was held and the body was later found outside, trained MMA fighter and Boston police sergeant
Jennifer McCabe - Sister in-law to Brian Albert, inserted herself into the search for O'Keefe, attempted to direct the narrative, and attempted to hide/destroy incriminating evidence
Colin Albert - Related to Brian, a local high school football player known to have been confrontational with his neighbor John O'Keefe
Michael Proctor - State Trooper who wrote the criminal complaint for the arrest, failed to disclose close ties with the Albert family and restricted access to Geofence data for the Defense
Thomas Keleher - Neighbor to Brian Albert, Deputy Chief of the Canton Police Department, claimed his Ring camera didn't see anything
Brian Tully - State Police Lieutenant, actively delayed the SERT team in conducting a search of the crime scene

Karen Read had dropped off her boyfriend John O'Keefe to a party at the Albert house and when he neglected to respond to her texts asking if he got in okay she pulled away. People at the party say he never entered but his geodata shows from where he was dropped off he had walked approximately eighty steps then climbed the three flights of stairs inside the Albert House. One witness named Ryan Nagel had originally gone there to pick up his sister Julie Nagel (before she came out and told him she intended to stay the night). Ryan saw Read drop O’Keefe off and told police that he did not see any damage to her vehicle, hear any screams, or witness her operating the vehicle erratically.

The allegations purport that Karen Read hit John O'Keefe with her car, breaking a tail light and scattering glass at the scene of the crime. But no glass was found when they conducted their initial searches. Video evidence suggests she broke her tail light after his death when she accidentally backed into O'Keefe's car the following morning as she left his home to worriedly go search for him.

Glass was only found at the scene of the crime after her broken tail light was observed by Trooper Michael Proctor and her car was taken into police custody. The broken glass found at the scene was supposedly spotted from an officer in a moving vehicle after several teams of officers had already swept that area on foot multiple times. The on foot officers cleared off the scene "pretty good" with leaf blowers and still managed to find frozen droplets of blood in the snow yet somehow missed tail light glass that another officer later supposedly spotted easily while just driving by. A photo of the crime scene taken at the location indicated shows no evidence of broken glass during the earlier search.

The SERT team was contacted by Brian Tully but informed that they did not have permission to search the scene yet. Trooper Proctor's sworn affidavit showcased a provably false timeline, which covered up that he and certain personnel at the Canton Police Department simultaneously had unfettered access to both Read's SUV (and it's tail lights) and the crime scene before the SERT team came in to conduct their search.

John O'Keefe was found with his eyes swollen shut, both black and blue. Multiple cuts and fractures on his head. And defensive injuries on his hands consistent with a brutal fight. He also had lacerations on his arm consistent with dog bites, and Brian Albert the owner of the house had a former police K-9 that was the family dog for seven years before inexplicably disappearing, supposedly having been re-homed sometime after the body was found. It's also worth it to note Brian's MMA training and Colin's previous altercations with O'Keefe and propensity for violence. Colin posted a picture of himself with some friends a few days later where his knuckles are noticeable injured in a manner consistent with a fight.

Jennifer McCabe had claimed that she went straight home around 1:30 that night with her husband and gone right to sleep, but in fact they had left about seventeen minutes later and drove two of Brian Albert Jr's friend home. One of whom was Julie Nagel, the girl who had just a few hours earlier told her brother Ryan she was going to stay the night there. On their way they passed by O'Keefe's residence with Read's car in the driveway. When she did get home that night her location data showed she did not sleep, but instead paced around her home.

After partying the night before until about 2AM, Jennifer McCabe was surprisingly wide awake the following morning at just before 5AM to receive the worried call from Karen Read. Despite not being close friends with Karen Read she insisted that she be brought along to help search for him. When Karen arrived to grab her she insisted again that they drive back to near where Karen had just come from to pick up another friend to help with the search. This critically delayed the discovery of the body.

Jennifer McCabe did a google search for how long it takes to die in the snow several hours before the body was discovered, her search included a specific typo ("hos long to die in cold"). She then tried to delete the search.

Jennifer later searched for how long to die in cold again after they found the body that morning, asserting that Karen had yelled at her to google it. But when she searched it she searched it with different typos, and then she made sure to search it yet again a third time, so that it would then include and match the exact typos she had in her original search from the night before. State Police had imaged Jennifer McCabe's iPhone 11 but instead of turning over this full and complete image to the Defense they had a Trooper named Guarino prepare a Cellebrite Extraction Report which purported to be a "Full File System Extraction" from the phone, which notably omitted her search history from that evening.

Jennifer claimed that Karen spotted the body first and that her and the other woman were confused because they couldn't see anything at all, but the snow on the ground was less than an inch and was largely reportedly accumulated on his pants legs. Defense maintains he was a stark and apparent figure easily standing out on the long flat lawn.

Neighbor Thomas Keleher who is a Deputy Chief at the Canton Police Department had a Ring doorbell camera which was positioned in such a way that it should have picked up John O'Keefe's body. But he claimed his Ring camera did not pick up anything of note and the video was never subpoenaed by the police.

TL;DR - It's likely that John O'Keefe was beaten to death and attacked by a dog at Brian Albert's house party and then left for dead in the snow. Then the whole thing was covered up by family members and police who were close to the Albert family, who framed O'Keefe's girlfriend Karen Read for the crime under the guise of vehicular manslaughter.