Becky Watts murder trial: Stepbrother 'had sexual motive' Published duration 7 October 2015

image copyright Avon and Somerset Police image caption Becky vanished on 19 February and her body parts were discovered 11 days later

Teenager Becky Watts was murdered and dismembered by her stepbrother and his girlfriend in a "sexually motivated" attack, a court has heard.

Body parts were found in a garden shed several days after she disappeared from her family home in Crown Hill, Bristol.

Nathan Matthews, 28, and Shauna Hoare, 21, deny murder. It is alleged Mr Matthews directed police to her body.

Bristol Crown Court heard the pair held "a shared unnatural interest in attractive teenage females".

image copyright Julia Quenzler image caption Nathan Matthews and Shauna Hoare deny a charge of murder

In a statement given to police, Mr Matthews admitted killing Becky and storing her body parts at 9 Barton Court, the trial heard.

He said he had strangled the teenager after trying to kidnap her.

Prosecutor William Mousley QC told the jury Mr Matthews had an "apparent dislike of Becky" and said he wanted to scare her and teach her a lesson.

Mr Matthews denies charges of murder and conspiracy to kidnap.

Miss Hoare denies murder, conspiracy to kidnap, perverting the course of justice, preventing a lawful burial and possessing a prohibited weapon, namely two stun guns.

In court: Jon Kay, BBC News

Jury told Becky's blood was found on the door frames outside her bedroom. Some of which contained Nathan Matthews' fingerprints

Prosecutor said evidence found on phones/computers showed Mr Matthews and Miss Hoare shared sexual interest in teenage and petite girls

Two stun guns were found at home of Mr Matthews and Miss Hoare, the court was told. Prosecution said they were ordered in name of Shauna Phillips

Becky's mother - Tanya Watts - left the courtroom in tears as the prosecution gave details of what is alleged to have happened to her daughter

Jury shown CCTV footage of Mr Matthews buying a power saw at B&Q in Horfield which, according to the prosecution, was for dismembering Becky's body

Either Mr Matthews or Miss Hoare searched YouTube for "Do you want to hide a body?" the day after the alleged murder, the jury is told

Prosecution said Mr Matthews "appeared to be genuinely concerned" when he opened the door to police looking for Becky

Extremely graphic description given to the court about the discovery of the teenager's dismembered body

image copyright Julia Quenzler image caption Prosecutor William Mousley QC (right) told the court Becky's body had stab and slash wounds caused after death

The court heard Becky was alone at her St George home where she lived with her father Darren Galsworthy and stepmother Anjie - Mr Matthews' mother - on 19 February, when the accused arrived just after 10:50 GMT.

On their way they stopped at a Tesco supermarket to buy batteries "possibly" for stun guns, the jury was told.

"She was suffocated, despite her fighting for her life. There followed a deliberate, carefully planned and grotesquely executed plan to cover up her killing," Mr Mousley said.

Her body was placed in the boot of the couple's car and they remained inside the house for much of the rest of the day, during which time other family members arrived, the trial heard.

'Violent struggle'

Sometime after 18:00 they left Crown Hill for their home in Cotton Mill Lane, Bristol, where they ordered takeaway food.

"All apparently normal behaviour, other than the fact that they had a dead body on their hands," said Mr Mousley.

Becky was reported missing the following day. After a huge police search, her body parts were discovered in a garden shed at a house in Barton Hill, Bristol, on 2 March.

She had 15 stab wounds to the abdomen and a further slash wound which were caused after death, the prosecutor stated.

Various injuries "were consistent with a hand being held over the mouth, causing suffocation" and also suggested "a violent struggle".

Mr Mousley told the jury the day after Becky's death Mr Matthews bought bottles of drain cleaner and 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," he said.

"He made it plain that he needed that saw and he needed to have it that day."

The jury was given a graphic description of the moment when police went to the shed in Barton Hill and found several suitcases, a bin bag and a blue plastic box containing body parts wrapped in plastic.

Other items found included handcuffs, a knife, scissors, some clothing and layers of cling film.

CCTV footage was played which the prosecution alleged showed Becky's body being moved from the couple's home to the Barton Hill address, 80 metres away.

image copyright Avon and Somerset Police image caption Karl Demetrius and his girlfriend Jaydene Parsons admitted assisting an offender

Another couple, who stored the dismembered body in their 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 the charge at an earlier hearing at Bristol Crown Court.

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

Donovan Demetrius, 29 and James Ireland, 23, are also charged with assisting an offender.

The trial, which is expected to last six weeks, continues.