Brianna Grier, woman who fell out of moving police car, died of 'severe blunt force injury' to the head: Autopsy

Brianna Grier, the Georgia woman who died after falling out of a police car last month, died from a severe blunt force injury to the head, according to the preliminary findings of an independent autopsy ordered by her family.

"In this case, the cause of death is consistent with the severe blunt force injury that occurred inside of the head," Dr. Allecia Wilson, a pathologist and the director of autopsy and forensic services at the University of Michigan, said at a press conference Monday to announce the findings.

Grier's medical records from Grady Memorial Hospital in Atlanta showed she had two fractures, hemorrhaging and a subdural hematoma after falling out of a moving police car while handcuffed on July 15, according to Wilson.

The 28-year-old mother of two was arrested by Hancock County Sheriff's Office deputies Lt. Marlin Primus and Timothy Legette on July 15 after Grier's mother called 911 to report that her daughter was experiencing a mental health crisis. According to the Georgia Bureau of Investigation, Grier fell out of the car's rear passenger door after it was not closed prior to transporting her to the sheriff's office. She had been handcuffed in front of her body and was not wearing a seatbelt.

The results of an official autopsy being conducted as part of the Georgia Bureau of Investigation's review of Grier's death are still pending.

The Georgia Bureau of Investigation told ABC News it did not have any investigation updates or comments to share at this time.

Body camera footage released in late July showed that the deputy thought he had closed the door, according to the Georgia Bureau of Investigation. The 10-minute clip shows officers struggling to get Grier into the backseat of the police car, but does not show how she ended up falling out of the vehicle.

"To put a handcuffed person in the back of a police car unrestrained ... you can use your own common sense as to what likely happened, especially when we look at the pathology from the MRI reports about the violent trauma -- the severe trauma and severe blunt force trauma -- that caused her to be knocked into a coma and to succumb six days later," attorney Ben Crump said Monday.

"So we continue to demand answers for this young Black mother who was experiencing a mental health crisis. She hadn't committed a crime. She deserved to be protected like somebody worthy to protect and serve," Crump added.

The body camera footage showed one deputy approach Grier as she lies in the road after falling out of the vehicle while saying, "How is your back door open?" to the other deputy.

Grier's mourning parents spoke at the press conference asking for transparency and answers for their grandchildren, 3-year-old twins Maria and Mariah. They said they still haven't been able to explain the tragedy to them.

"That's why we're here. We're trying to get answers so we can finally tell them what's going on and what's happened to their mama," Brianna's father, Marvin Grier, said.

"I just want justice for what happened to my daughter Brianna Grier," Mary Grier added, saying that she doesn't want this to happen to any other mother.

Grier's funeral is set to take place Thursday at West Hunter Baptist Church in Atlanta.