Georgia mom Brianna Grier died after falling from moving police car. Her family is suing.

Attorneys for the family of Brianna Grier filed a wrongful death lawsuit Wednesday in the case of the 28-year-old Black woman who died six days after falling out of the open door of a moving police patrol car in Georgia.

Attorneys say Grier, the mother of then-3-year-old twin girls, was having a mental health crisis when members of the Hancock County Sheriff’s Office arrested her last July at her parents' home in Sparta, about 70 miles east of Atlanta.

Grier was handcuffed and had no seatbelt on when she fell out of the open door and hit her head on the road, according to the Georgia Bureau of Investigation. She suffered brain trauma and went into a coma on July 15. She died on July 21.

The lawsuit, filed by attorney Ben Crump and co-counsel Eric Hertz, names three members of the Hancock County Sheriff's Office and claims they participated in gross negligence that led to Grier’s death. The sheriff's office did not immediately respond to a request for comment.

"There is no excuse, no justifcation, for why Brianna Grier is dead and why she died in such a horrific manner," Crump said in a press conference Wednesday in Decatur, Georgia, alongside members of Grier's family. "Her daughters continue to ask questions all the time about their mother."

The Georgia Bureau of Investigation closed its probe of the incident in November, and the Ocmulgee Circuit District Attorney decided against bringing the case to a civil or criminal grand jury.

Brianna Grier called 911 for mental health help, lawsuit says

Grier's mother called police that day because Grier was having a mental health crisis, and she wanted officers to bring Grier to a hospital, according to the lawsuit. Grier also called 911 and told an operator she was having an anxiety attack and needed medicine, the lawsuit states.

The two responding officers knew Grier had been diagnosed with schizophrenia, and both knew she was having a mental health episode, according to the lawsuit. Yet one of the officers announced he was charging Grier with "public drunk" and handcuffed her. Later tests found no alcohol in Grier's system, the lawsuit states.

"This young, beautiful Black woman needed help. The police came and put her in handcuffs," Crump said.

Crump said Grier's mother forever questions the decision to call police that day. He said Grier’s father died of congestive heart failure two months after his daughter's death, from a "broken heart."

Mary Grier, who held up a framed portrait of her daughter, said she is "truly broken." She said she tells her granddaughters that their mother has gone "home to be with god."

Lottie Grier, Brianna's older sister, is helping raise her nieces. "She didn't deserve the way she died," Lottie Grier said. "To see her babies have to grow up without her, it hurts."

Body-cam video shows Brianna Grier motionless on the ground

Body-cam video released weeks after the incident shows Grier repeatedly telling police officers that she was not drunk and asking deputies to give her a breathalyzer test.

Officers can be seen placing Grier in handcuffs and attempting to put her in a squad car. The video shows Grier crying and yelling on the ground.

The GBI said Grier refused to get in the patrol car. According to the agency, she said she was going to harm herself.

At one point, the video shows a deputy taking out his taser as Grier yells, "You can tase me. I don't care." The deputy appears to electrify the taser, which crackles, and tells Grier to "get up." The deputy then tells Grier he is not going to tase her.

Grier continues to yell on the ground as the deputy appears to pick her up, put her in the patrol car and close the driver-side door.

In its review of the incident, the GBI concluded the back door on the passenger side of the patrol car was never closed, even though one of the deputies thought he closed it.

Video from moments after Grier fell from the car appears to show her unconscious, face down on the ground. She does not appear to respond as a deputy prods her on her right side. One of the officers instructs the other to turn off his body camera, and he does, according to the suit.

Grier's skull cracked in two places, and she suffered a brain bleed, Crump said.

The officers told the sheriff Grier "jumped out" of the car, and the sheriff repeated the claim to the media, the suit states. But the officers later told the GBI they did not see how Grier exited the vehicle, according to the suit. The lawsuit alleges Grier was ejected from the back seat.

Georgia NAACP leader: More mental health resources needed

Gerald Griggs, president of the Georgia State Conference of the NAACP, said the state "has a problem" with police brutality and does not properly respond to mental health emergencies. He called on the governor to fully fund mental health facilities.

"Far too often we have individuals in mental health distress, and the only organization or the only individuals that can respond are law enforcement. And in this case, like countless other cases, it ended in the untimely and illegal death of an innocent person," Griggs said.

The lawsuit comes two days after Crump and other activists stood on the steps of the Georgia State Capitol to announce the findings of an independent autopsy in the case of a LaShawn Thompson, a 35-year-old man with diagnosed mental health issues who was found unresponsive and covered in bug bites at Fulton County Jail last fall.

Thompson died due to "severe neglect" from jail staff, the autopsy concluded, and attorneys for his family are calling for criminal negligence charges.

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Contributing: Christine Fernando, USA TODAY

This article originally appeared on USA TODAY: Georgia mom Brianna Grier died after arrest. Her family is suing.