UPDATED 7/28, 9:52 p.m. ET: New details have emerged in the death of Brianna Marie Grier, a 28-year-old woman who died while in police custody.

According to the Georgia Bureau of Investigations, the woman fell out of a moving police car after deputies failed to close a rear passenger door. The GBI says its team came to the conclusion after reviewing bodycam footage, conducting multiple interviews, and running a series of mechanical tests on the cruiser to rule out any malfunctions.

Investigators say two Hancock County deputies placed Grier in the patrol car after she expressed her intention to harm herself. The GBI states the deputies had opened both rear doors as they attempted to put Grier in the backseat of the vehicle. Once they successfully got her in the cruiser—handcuffed in the front of her body with no seatbelt—the deputies closed the rear driver’s door but left the rear passenger door ajar.

“The deputies left the scene and drove a short distance,” the GBI wrote. “Body camera footage reveals the deputies had no other contact with Grier from the time she was placed in the car until she fell out of the moving car.”

The investigation is ongoing. 

See the original story below.

The Georgia Bureau of Investigations is looking into the death of a Georgia woman who died last week after falling out of a moving police car.

WMAZ reports Brianna Grier, 28, was pronounced dead on July 21 following an “in-custody incident with Hancock County Sheriff’s Office deputies.” The incident occurred on July 15, when Grier’s mother called police for help because her daughter was having a schizophrenic episode. 

“Grier was arrested at the home,” the GBI said. “While deputies were taking Grier to the Hancock County Sheriff’s Office, Grier fell out of a patrol car and sustained significant injuries.  She later died because of those injuries.”

According to Brianna’s father, his daughter suffered a head fracture and was airlifted to a local hospital. After remaining in a coma for several days, Brianna was taken off a ventilator after a doctor told relatives that she was “brain dead.”

Geoffrey Alpert, a professor of criminal justice at the University of South Carolina confirmed to NBC News that patrol cars are “ALWAYS supposed to be locked from the inside.”

“Otherwise,” he added, “prisoners would be letting themselves out all the time.”

“If she got out the car, they had to let her out the car,” Brianna’s mother, Mary Grier, told WMAZ. “That’s my interpretation, because in a police car, you can’t open the door from the inside, it had to be the outside.”

The GBI investigation remains active and ongoing.