The Whitehead twins did everything together, including kill their mother.

Warning: the following contains details of family violence that may be distressing. If you or someone you know is dealing with family violence, support is available. Please call 1800 RESPECT on 1800 737 732.

Jasmiyah Whitehead ran toward the road screaming, waving her arms at the police car that happened to be driving past her home in Conyers, Georgia. She told the Deputy that she and her identical twin sister, Tasmiyah, had come home from school to find their mother dead, submerged in their bathtub.

Jarmecca “Nikki” Whitehead, 34, had been beaten and stabbed 80 times with a kitchen knife. The house, in which she lived with her 16-year-old girls and her boyfriend, told of her violent end. There were blood stains on the carpet, on the walls, drag marks between the living room and bathroom.

“It was the bloodiest scene I think I’ve ever been to,” Lt. Chris Moon of the Conyers Police Department later told NBC.

As investigators descended on the crime scene that afternoon — January 13, 2010 — the girls were taken away from the horror to the local police station. On the way, Tasmiyah began biting her arm. A nervous habit, she told querying officers, just something she’d do when she was upset.

A short time later, safe in an interrogation room, they were consoled by detectives.

“These two girls were hugging each other in each other’s arms, and when I said, ‘What can I do to make this easier for you?'” Det. Ken Swift told True Crime Daily. “They turned and looked at me and they said ‘Can we watch CSI?’

“Immediately the hairs on the back of my neck stood straight up. Essentially it was right then that it was like, OK, this is— something was very, very off.”

“They seemed very innocent and sweet.”

Nikki was 17 when she gave birth to Jasmiyah and Tasmiyah — or Jas and Tas, as they were known. The girls spent their childhood in the care of their great-grandmother, Della Frazier, before Nikki took custody when they were 13 and moved them to Conyers.

They were Girl Scouts and honour-roll students, but once in high-school they rebelled against their mother’s discipline. According to Rockdale News, a court was later told that Nikki believed the girls were sexually active, using marijuana and skipping school: “The girls, on the other hand, were resentful of their mother’s attitude to them,” County District Attorney Richard Read later told a court. “They believed she was a hypocrite because she was promiscuous and used marijuana.”

Their strained relationship led to several altercations and multiple 911 calls. One incident on June 28, 2008, brought Conyers Police officer Myra Scruggs to their house.

"The girls seemed very innocent, very sweet, but the look in Nikki's face, she was fearful of those children. She knew that they worked together," Officer Scruggs told True Crime Daily.

Unsettled, Scruggs left the home, but remained in the area. Within minutes, Nikki made a second 911 call saying she'd been attacked. The girls claimed to have been defending themselves against an assault by their mother.

"[Nikki] had scratches on her neck, scratches on her chest, and she was hysterical," said Officer Scruggs. "The girls, on the other hand, had no marks on them, no indication that really they had been in any kind of altercation. Talking with them, I didn't believe a thing that the girls had said. You could have been two strangers and there would have been more emotion shown."

A juvenile court declared the twins to be "ungovernable", returned them to the custody of their great-grandmother and ordered them to undergo counselling along with their mother, Rockdale News reported. They remained in Della's care until they landed themselves back court for truancy and running away from home, and a judge put them back in Nikki's custody yet again.

The decision, on January 5, 2010, "caused chaos in the hallway of juvenile court," D.A. Read later told a court, according to Rockdale News. Jasmiyah was the most upset and "said in the presence of the victim [Nikki]...‘If I have to go live with you again, I'm going to kill you.'"

A week later, Nikki was dead.

The truth emerges.

In the hours after Nikki Whitehead's murder, police turned their attention to Jas and Tas. They'd both worn gloves to the station, and didn't remove them once inside. When police asked to see their hands and arms, both had bite marks and scratches. The twins dismissed the wounds as the result of an earlier fight they'd had.

Then, once separated, their account of that day's events began to unravel. Though they said they'd only been 10 minutes late to school the morning of the murder, and that they'd walked there, surveillance footage showed them hitching a ride from a stranger hours later.

Back at the crime scene, investigators found their bloodied clothes in the washing machine, evidence of bleach on the carpet as if someone had attempted to clean the blood and, later, hair belonging to one of the girls was found in Nikki's teeth. The bite marks on Tasmiyah's left arm — the ones she had tried to cover up on the way to the station — matched Nikki's dental records, Rockdale News reported.

But it took four months for police to pull together all the evidence. Four months during which the twins were placed in the care of the Division of Family and Children Services and lived separately. They continued at the same school, hung out with friends as normal, even went to their school formal.

They were finally arrested on May 21, 2010, charged with felony murder and aggravated assault. They pleaded not guilty.

But still awaiting trial nearly four years later, and faced with a plea deal, they ultimately confessed to voluntary manslaughter.

Police tapes show Jasmiyah describing that on the morning they killed their mother, they'd fought with her over the fact they were running late for school. They claimed she threatened them with a pot from the kitchen, which escalated into an all-in brawl.

"She just started waving the pot around, things like that, whatever, so I guess she was trying to hit us with the pot," Jasmiyah told detectives.

She wrestled the pot from Nikki, who then grabbed a steak knife. She never used it. Jasmiyah struck her with the pot first. They then choked her with a ribbon. As they screamed and wrestled, Nikki bit, punched and scratched the girls, until Tasmiyah attacked with a knife.

"I think I picked up a knife and I stabbed her," she said. "I think I stabbed her in the stomach. ... It was multiple times."

Together they dragged her into the bathtub, where Nikki spoke her final words: "[She said] She hate us, she hate us... [That] We're going to jail," Jasmiyah said. "I told her I was sorry."

Shocked by what they'd done, the pair "cried for a long time". They then attempted to clean up the scene, changed their clothes and went to school.

"It wasn't a fight like on the street; it was more a fight until somebody die," Jasmiyah confessed to police. "I didn't hate her, and Tas didn't hate her either. I guess it... heat of the moment and built up anger between all three of us."

The twins were each sentenced to 30 years in prison in 2014.