Yulia Ivanova, an official spokesperson for Moscow's Interior Ministry, said: "[The suspect] had waited until the parents left with the older child, and for unknown reasons committed murder of the child, set the apartment on fire and left the scene of the crime."

The dead child is said to have had learning difficulties and could not walk properly. Her parents had taken her to China for treatment, and were saving money to travel for subsequent care in Germany. 

The remains of Nastya were found in a cot at the flat, dressed in night clothes including a T-shirt and shorts. At one point the shocking video shows the moment the woman raises the blood-covered head in the air while holding her index finger aloft. The station was closed after the woman shouted "I'm a terrorist" and threatened to blow herself up. It was searched for explosives but given the all-clear by specialist officers a short time later.
Staff working in shops nearby the station were also ordered to evacuate.  Eyewitnesses at Oktyabrskoye Pole underground station said that the woman screamed:"My child was killed… I will blow up everyone." She is heard shouting that she has been “cursed” and “destroyed” “so many times," before saying: "I hate democracy. I'm your suicide bomber… I'm going to die in a second. The end of the world."
Witness Alyona Kuratova told Russia's Rain TV: "I came out of the shopping centre and they tried to not let me through. There were a bunch of people there, running, screaming 'bomb, bomb'. I saw that a woman was walking near the Oktyabrskoye Polye metro, near the road, all in black. She had not even some kind of bundle, but a head. "Maybe it was a child's head, like they were whispering in the crowd. She was shouting something." Dramatic CCTV footage also captured the moment police swooped and dragged Bobokulova to the ground in a tense stand-off. 

A spokesman from the Investigative Committee of Russia said: "Given the clearly inappropriate behaviour of the person detained, investigators immediately appointed her to a forensic psychiatric examination to determine their ability to realise the significance of their actions and deeds." Fire crews rescued four people and put out the blaze, but then found the child's beheaded body. Yulia Ivanova, an official spokesperson for Moscow's Interior Ministry, said: "[The suspect] had waited until the parents left with the older child, and for unknown reasons committed murder of the child, set the apartment on fire and left the scene of the crime." 

The dead child is said to have had learning difficulties and could not walk properly. Her parents had taken her to China for treatment, and were saving money to travel for subsequent care in Germany. She had a 15-year-old brother and her family from the Oryol region were renting the apartment. Her mother - named locally as Ekaterina Meshcheryakov - reportedly works at a wedding shop while her father is understood to be a technician at a mobile phone company. The child's mother was taken to hospital after collapsing when she learned of the news, according to reports. The dead child’s parents are said to have noticed Bobokulova’s “unstable mind” but believed she was suffering with fatigue.  However a family friend claims Ms Meshcheryakova - known as Katya - trusted her nanny.  She said: “She is a shrewd woman, she would notice. “She trusted Gyulchekhra fully. More than this she considered her family member. Everyone called her just Gulya. “They all lived in one flat. That is why Katya and Vladimir rented a big flat with two bedrooms, so they all had enough space.”

She has been charged with murder and is undergoing psychiatric testing. The parents told police the nanny had been working for them for more than 18 months and a source said that she was "drugged". Sources say the nanny did not want to hide from police and aimed to attract attention for the crime she had committed. She had not intended to deliberately set fire to the flat to destroy evidence and wanted the parents to know who had killed their daughter. The woman had a valid residency permit for Russia but was working illegally. Officials revealed she didn't have a work permit. The nanny faces up to 20 years in jail if she is deemed psychologically fit to stand trial.
Police say they are not treating the incident as terrorism.