Becky Watts was murdered and cut up with a power saw after her step-brother and his girlfriend planned to kidnap her for sex, a court has heard.

The 16-year-old was killed in a bedroom of her home in Bristol by Nathan Matthews and Shauna Hoare on February 19 this year, jurors were told.

Prosecutor William Mousley QC said the pair then spent three days cutting up the body and 'carefully packaging each individual parcel, using metres and metres of clingfilm'.

Matthews, 28, has confessed to killing Becky but he says there was no intention to kill and he acted alone.

Bristol Crown Court heard he ordered a takeaway meal on the night of her death, then went to a B&Q store the following day and bought a power saw to use in the disposal of her body.

A post-mortem examination found that, after her death, Becky was stabbed 15 times in the abdomen. She had been dismembered across her neck and above her knees, elbows and wrists.

Becky Watts went missing from her home in Bristol in February. Two people are now on trial for her murder

Accused: Becky Watts, far-right, is pictured at the wedding of her father Darren Galsworthy and her step-mother Anjie. Also in the picture are the accused Nathan Matthews and Shauna Hoare

Summarising the prosecution's case, Mr Mousley said: 'Rebecca Watts, known to all as Becky, aged 16, was killed in her bedroom. She was suffocated, despite her fighting for her life.'

Becky's mother, Tanya Watts, fled the court room in tears as the case was opened to the jury.

Mr Mousley said the police investigation suggested Matthews and Hoare, 21, intended to kidnap Becky using a stun gun.

He said: 'Evidence was found on telephones, computers and computer-related equipment connected to both Nathan Matthews and Shauna Hoare which showed a shared sexual interest in teenage and petite girls.

'Also found at their home were two stun guns, which were prohibited weapons and which may have been intended for the use in the planned kidnap.'

The court heard that, on the morning of Becky's death, Matthews and Hoare drove to Becky's family home, stopping off at a Tesco Express to buy some batteries, which Mr Mousley suggested were for the stun gun.

Becky died at some point between 11am and the early afternoon and her body was put in the boot of Matthews' Vauxhall Zafira car.

Mr Mousley said CCTV footage showed Matthews and Hoare driving to their home shortly before 7pm, with a child captured on camera sitting in a back seat.

They then ordered a Chinese takeaway from Laws Kitchen - where Matthews worked - before settling down to watch the television for the night.

'All normal behaviour, other than they had a dead body on their hands,' Mr Mousley said.

Becky's step-brother Nathan Matthews and his girlfriend Shauna Hoare are on trial, charged with murder

Prosecutors say Matthews and Hoare spent three days cutting up the body and packaging it in clingfilm

Later that evening Hoare's mobile phone was used to search YouTube for 'Do you want to hide a body?', the court was told.

Describing the aftermath of the killing, Mr Mousley said: 'Following her removal from her home, over the course of the next few days, her body was cut up with a knife and a power saw.

'The parts [were] carefully packaged and then moved to another address... where they were intended to be stored, probably temporarily, until a final solution could be found.'

BECKY WATTS MURDER TRIAL: WHO ARE THE ACCUSED? Nathan Matthews, 28, denies charges of murder and conspiracy to kidnap. Shauna Hoare, 21, denies murder, conspiracy to kidnap, perverting the course of justice, preventing a lawful burial and possessing a prohibited weapon, namely two stun guns. Donovan Demetrius, 29, and James Ireland, 23, deny assisting an offender. Karl Demetrius, 29, and Jaydene Parsons, 23, have already pleaded guilty to assisting an offender. Advertisement

Mr Mousley said that day after Becky was killed, Matthews drove to Rajani Superstores in Bristol and purchased two bottles of one-shot drain cleaner before heading to a B&Q store in Horfield.

He arrived there and was captured on CCTV buying a circular power saw, gloves, a face mask and goggles.

'When he was there buying the saw he queried the price he was being charged for it as it didn't correspond with the price on the display,' Mr Mousley said.

'He made it plain that he needed that saw and he needed to have it that day. The prosecution say it became clear as the police investigation continued that all those items bought at B&Q were needed to be used in the dismemberment of Becky Watts' body.'

The day after that, Matthews and Hoare went to Asda in the Bedminister area of Bristol and purchased, in addition to groceries, black bags, rubble sacks, rubber gloves and three rolls of clingfilm.

The following day, Matthews and Hoare went to the Broadmead shopping centre in Bristol city centre and bought more rubble sacks and tape, as well as a sponge, from a branch of a 99p store and Wilko.

The pair then went to Sainsbury's in Brislington and purchased more tape, the prosecution allege.

A court sketch shows Matthews (back row, far left), Hoare (back row, far right), and co-defendents Ireland (front row, centre left) and Donovan Demetrius (front row, far right), who are charged with assisting an offender, in the dock at Bristol Crown Court today

Donovan Demetrius (left) and James Ireland (right) are also charged with assisting an offender

Mr Mousley said: 'The prosecution suggests that what was happening on February 20, 21 and 22 is the lengthy process of cutting up and carefully packaging each individual parcel, using metres and metres of clingfilm and in particular the cleaning up, particularly in the bathroom.'

On the evening of February 23, four days after the killing, Matthews is thought to have rung his friend Karl Demetrious, who lived about 80 metres from their home.

Police visited Matthews and Hoare's home the following morning and noticed the house was cluttered but the bathroom was 'completely clean'.

Matthews and Hoare were interviewed a number of times over the following days but repeatedly told police they hadn't seen Becky. But he eventually confessed to strangling and killing Becky in a bungled abduction on March 2.

Mr Mousley added: 'Nathan Matthews finally admitted the killing, stating that he had tried to kidnap and imprison Rebecca Watts and said that he had strangled her.

Becky sent her friend a final text shortly before she is believed to have been killed at her home

'He said he had acted alone in the killing... [and] in the subsequent dismemberment and in arranging for the removal of her body parts.'

The court heard today that Becky's remains had been carefully packaged and covered in clingfilm and concealed within a blue plastic box, two black suitcases and a rucksack.

Jurors were told that Becky's torso was wrapped up in a shower curtain inside the plastic box - containing cat litter, which can be used as a decontaminator.

Police also recovered the circular saw, clingfilm, tape, female clothing, screwdrivers, scissors, gloves and face masks containing Matthews' DNA, a knife, bleach spray, female clothing and an iPhone and laptop from the shed.

Hoare's DNA was also recovered from a facemask found in the shed, along with a blue T-shirt also found.

The court heard that, on a couple of occasions in 2014, Matthews and Hoare engaged in a consensual threesome with a friend of Hoare, which he filmed on his mobile phone.

Mr Mousley alleged that internet searches carried out in November and December 2014 showed Matthews and Hoare had a 'shared interest' in teenage girls.

Police also recovered a video showing the rape of a teenage girl in which the attacker put his hand over her mouth.

Jurors heard that Becky had told a friend she was scared of Matthews and that he had threatened to kill her in 2013.

After his arrest, Matthews told police that he wanted to kidnap Becky 'to scare her and teach her a lesson because she was selfish and treated his mother badly'.

He said he had taken a large bag, a stun gun, handcuffs, tape and a mask to Becky's home but his mask slipped and she saw him, so he put her in the bag and strangled her.

Becky's father Darren Galsworthy (right) and grandfather John Galsworthy (left) arrive at court today ahead of the trial of her alleged killers

Family members and friends including Becky Watts' uncle, Sam Galsworthy (centre and aunt Sarah Broom (right) arrive at Bristol Crown Court this morning

Friends and family of teenager Becky Watts leaving Bristol Crown Court after the opening day of the trial

The trial, before High Court judge Mr Justice Dingemans, is expected to last for up to six weeks. Pictured: The teenager's friends and family heading home

He said he put Becky's phone, laptop and some bedding and clothing into the bag and placed it in his car.

'He said he waited until Shauna had gone to bed before putting the bags into the house,' Mr Mousley told the court.

In addition to their apparent dislike of Rebecca Watts, there is good reason to believe that there was also a sexual motive behind the scheme, arising from a shared unnatural interest in attractive teenage females. Prosecutor William Mousley

'He moved the bag containing Becky's body and put it in the bath. He said he cut up her body with the circular saw, wrapping up the body parts, carrying them downstairs and hiding them.

'He stated that Shauna Hoare didn't know anything about what he had done because if she had known he believed she would have called the police,' Mr Mousley said.

Hoare denied all knowledge of Becky's death and stated she had no interest in kidnapping teenage girls.

Karl Demetrius, and his girlfriend, Jaydene Parsons, have admitted assisting an offender after they stored Becky's body in their garden shed.

However, they maintain they 'did not know or believe' the bags contained Becky's body.

Donovan Demetrius, 29, of Bristol, and James Ireland, 23, of Avonmoth, also face trial accused of assisting an offender.

Mr Mousley said: 'Four others, acting together, including James Ireland and Donovan Demetrius, who, to varying degrees over a period of a week, helped in the hiding of her disguised remains in the knowledge that she had been killed or that some other significant offence had been committed.'

Forensic officers pictured during the investigation into Becky's disappearance and death

Becky's dismembered body was found in a shed in the garden of Barton Court, Bristol

On February 28, Ireland went out with friends and he said that the previous week he had been asked to help remove 'some stuff' - the proceeds of a robbery - and would be paid £5,000.

He told the friends he had used a van from work to transport the 'tightly packaged, slightly squidgy' packages from Cotton Mill Lane to Barton Court and would go on holiday with the money.

Neighbours noticed that the dogs belonging to Karl Demetrius and Parsons were kept out of the garden after Becky was put in the shed.

Mr Mousley explained that, following publicity about the arrests, James Ireland, Karl Demetrius, Jaydene Parsons and Donovan Demetrius had met at the home of Karl Demetrius and his girlfriend Parsons.

'The police were keeping observations and shortly after midnight arrested three of them as they were trying to leave,' the prosecutor said.

'Donovan Demetrius was inside when the house was then entered and later arrested. A search of the house and garden led to the discovery of the body parts of Rebecca Watts in a shed.'

Becky's funeral last year. Her disappearance and death came as a huge shock to the city of Bristol

Mr Mousley added: 'It emerged that Karl Demetrius and James Ireland had helped transport her body parts and other items used in her dismemberment in various bags to that address of Karl Demetrius and Jaydene Parsons, four days after her killing.

'Donovan Demetrius was present when they arrived and was regularly there up until he was arrested, assisted in the continued concealment.

'It may well be that initially they did not know that there had been a killing rather than another offence, drug related or robbery or stolen property but, as the days passed up to their arrest, it would have become increasingly obvious what had happened.'

Becky lived with her father Darren - who is married to Matthews' mother Anjie - in the St George area of Bristol.

Her father sat in the front row of the public gallery today, alongside Becky's uncle, Sam Galsworthy, and her grandfather, John Galsworthy. Becky's brother, Dan, and her aunt, Sarah Broom, were also in the public gallery.

Mr Galsworthy's partner Anjie - the mother of Matthews - was not present.

Six dock officers sat alongside the defendants in the dock. The trial, before High Court judge Mr Justice Dingemans, is expected to last for up to six weeks.

COUPLE WHO STORED BODY IN GARDEN SHED ADMIT ASSISTING OFFENDER A couple who had the dismembered body of teenager Becky Watts stored in their garden shed have pleaded guilty to assisting an offender, it can be reported for the first time. Karl Demetrius, 29, and his girlfriend, Jaydene Parsons, 23, admitted at an earlier hearing at Bristol Crown Court to a charge of assisting an offender. However, they maintain they 'did not know or believe' the bags contained Becky's body. Karl Demetrius, 29, and Jaydene Parsons, 23, have both admitted a charge of assisting an offender Prosecutor William Mousley QC told the court: 'Karl Demetrius says he believed it was cannabis but became increasingly suspicious that the contents related to Becky Watts. 'Jaydene Parsons says that she only formed the belief that the bags were related to criminal activity during the evening before her arrest.' Police recovered the body parts of 16-year-old Becky from the shed in the garden of the couple's home in Barton Court, Bristol, days after she had been reported missing. A judge had made an order preventing the media from reporting their guilty pleas until the trial of the other people allegedly involved in Becky's murder began. Karl Demetrius, and his girlfriend, Jaydene Parsons, have admitted assisting an offender after they stored the dismembered body of teenager Becky Watts stored in their garden shed Advertisement

How prosecutors claim the accused disposed of the body: Timeline of the killing of Becky Watts

February 19th -Watts returned to her home after a night away. Matthews and Hoare phoned to say they were coming round.

Matthews and Hoare drove towards Becky’s home at around 10.50am that morning, stopping off at a Tesco, which the prosecution say was to buy batteries, potentially for a stun gun.

At 11.03am Becky sent her last text message before she disappeared.

February 20th - The prosecution say Matthews purchased two bottles of drain cleaner before heading to a B&Q store to buying a circular power saw, gloves, a face mask and goggles.

February 21st - The prosecution say Matthews and Hoare went to an Asda and purchased, in addition to groceries, black bags, rubble sacks, rubber gloves and three rolls of clingfilm.

Police root through an area of land during the high-profile search for Becky Watts in February this year

February 22nd - Matthews and Hoare went to the Broadmead shopping centre in Bristol city centre and bought more rubble sacks and tape, as well as a sponge, from a branch of a 99p store and Wilko, the prosecution

The pair are also alleged to have gone to a Sainsbury's and purchased more tape.

February 23rd - Police called at Matthews and Hoare's home but there was no answer at the door and the curtains were drawn. The prosecution claim they moved the body parts to the shed of Karl Demetrius and Jaydene Parsons.

February 24th - Police launch media appeal for 'missing' Becky. Officers search Matthews and Hoare's home and find it messy apart from the bathroom.

February 28th - Forensic experts discover Matthews' fingerprints in Becky's blood on doorframes outside her bedroom, both he and Hoare were arrested on suspicion of kidnap.

March 2nd - Matthews made disclosures to detectives and officers went to the home of Karl Demetrius and Jaydene Parsons.

Parsons, Karl Demetrius and Ireland were arrested leaving the property, while Donovan Demetrius was arrested after police discovered Becky’s dismembered body in the shed.