(NewsNation) — A Georgia woman died falling out of a moving police vehicle after a deputy failed to close the rear passenger door, state investigators found.

Brianna Marie Grier, 28, died on Thursday, two weeks after she fell out of a Hancock County Sheriff’s deputy’s patrol vehicle, the Atlanta-Journal Constitution reported.

Grier’s family called the Hancock County Sheriff’s Office for help on the morning of July 15 because she was having a schizophrenic episode, according to local TV station WMAZ-13.

When they responded to the call, two Hancock County deputies arrested Grier.

Grier was on the ground and refused to get in the vehicle, and made a statement that she was going to harm herself. To get Grier in the car, one of the deputies walked around and opened the rear passenger side door, then quickly returned to the rear driver’s side door. Both deputies then put Grier in the car’s backseat, the GBI said. Although they closed the rear driver’s side door, they did not do the same for the passenger side.

The Georgia Bureau of Investigations, which was tapped to look into what happened, said Grier had been placed in the backseat of the car, handcuffed in the front of her body, with no seatbelt.

“The investigation shows that the deputy thought he closed the rear passenger side door,” the GBI said.

Body camera footage shows deputies had no other contact with Grier until she fell out of the moving vehicle.

The names of the deputies involved were not released.

Grier’s parents told WMAZ that the sheriff had initially told them their daughter had kicked her way out of the cruiser.

Mary Grier, Brianna’s mother, told WMAZ she was shocked when seeing her daughter in the hospital.

“If I had known it was going to turn out like this, God knows I wouldn’t have called to come and get her,” Mary Grier said. 

The Hancock County Sheriff’s Office declined to comment on the bureau’s findings Thursday to NBC News.

Sheriff Terrell Primus, however, addressed about a dozen demonstrators marching in Grier’s honor and offered his condolences to her family, according to the Union-Recorder.

He said body camera video footage would be released once the GBI’s investigation is complete, and that the department does not have anything to hide.

Civil rights attorney Ben Crump is now being retained by Grier’s parents, according to NBC.

“Brianna Grier was a beautiful young mother who should still be alive,” Crump said in a statement. “It is the responsibility of law enforcement to keep everyone in their custody safe and alive, including when there is a mental health crisis.”