Elena Karimova, 27, was caught on CCTV buying her children a chocolate bar

This is the appalling moment an 'evil' mother buys a last chocolate bar for her two young children at a filling station shortly before brutally killing them, says Russian law enforcement.

Divorcee Elena Karimova, 27, also bought lighter fuel which she used to burn the bodies of her daughter, Khadizha, four, and son Suleiman, two, who she strangled in the back seat of her rented Kia Rio.

The glamorous woman with 27,000 followers for her Instagram cosmetics business was detained on murder charges nine months ago and the case is soon to go to court.

The deeply shocking CCTV video was released today.

The mother is seen acting normally as she pays in advance for petrol plus the Snickers bar and barbecue lighter fuel.

Then she goes to her hired car — inside which are her two children — to fill up with fuel before returning to collect the items which she is seen carrying as she gets back into her car.

An hour or so afterwards she parked the car and strangled her children, it is alleged.

Deeply shocking CCTV video was released today shows Karimova buying a Snickers and lighter fuel

Then she took the bodies into woodland and used the lighter fuel to incinerate their bodies.

But the Nizhny Novgorod woman feared locals would see the smoke.

She used water to extinguish the flames on their burning bodies, and put the charred remains into her car, say state investigators.

Karimova went home for the night with the bodies in the car, it is alleged.

Next day on 26 April, she brought the burned corpses to an abandoned warehouse near the city and set fire to the building.

Firemen initially found what appeared to be one severely burned body after extinguishing the blaze.

'The fireman initially thought that the charred corpse belonged to a dog,' said local resident Evgeny Katyshev.

Elena Karimova and son Suleiman (left) and daughter Khadizha (right)

Karimova, pictured in court, reportedly parked her car an hour after she was caught on CCTV and strangled her children

'But when he came up closer, he realised these was the bodies of two children.'

'They were in unnatural poses, and rumours spread that they had been transported in a suitcase.

'The bodies were so damaged only one leg remained, and it was impossible to identify the gender of the corpses.'

Local people noticed her car at the scene and police interrogated her leading to her full confession, say detectives.

'I couldn't provide for my children,' she told officers, blaming money problems for her actions.

But later she retracted her admission that she had murdered her children.

After she strangled them, she took the bodies into woodland and used the lighter fuel to incinerate them

The woman claimed she had trouble raising Khadizha and Suleiman (pictured) because of a divorce

In her original court appearance she had acknowledged that she killed them saying: 'I'm very sorry for what happened. I do not even know how I could go about this.'

She added: 'I lived with my husband, and then we divorced and it became difficult to raise children.'

Despite her financial problems, she spend £470 a month on car rentals and took foreign holidays.

Shocked family members and friends said her action was 'totally out of character' and refused to believe she was capable of such barbarity.

Karimova also stole jewellery from a friend worth £1,600.

The man who rented her the car provided evidence to police that she had been responsible for the crimes, according to the Russian Investigative Committee which brought the criminal case against the mother.

The committee insist that she had no accomplices.

A Russian court heard she would regularly spend large amounts of money on holidays

The glamorous woman with 27,000 followers for her Instagram cosmetics business was detained on murder charges nine months ago

She underwent psychiatric tests and was found to be sane, say law enforcement officials.

After releasing the video, a key part of the case against her, the committee said: 'CCTV cameras at a filling station recorded on the day of the murder as a 27-year-old resident of Nizhny Novgorod filled the tank of a rented car, and also bought lighter fuel, and for children, who were in the car, the last chocolate bar of their lives.'

Her mother Natalia Testenkova was dumfounded immediately after the murder, saying: 'We do not believe this.

'She is the most loving mother.

'How could she kill her kids?

'We do not know what has happened, but we do not believe these are her kids that were found.'

But the investigation found they were her children, say law enforcement.

Her godmother Valentina Butnar said Karimova had been in a 'good mood' shortly before her children were killed.

'I just cannot believe this is true,' she said.

Two weeks before the alleged double murder the mother wrote on the birthday card of her daughter: 'You are my soul, my dearest little one, my long-awaited daughter….

'The one I live for. You are my copy.'