Becky Watts: Stepbrother and his girlfriend named locally as two arrested on suspicion of murder

Police have been given extra time to question suspects after the gruesome discovery

Rebecca Watts, 16, was last seen at her home in St George, Bristol at around 11.15am Thursday 19 February

Becky Watts' stepbrother and his girlfriend have been named locally as the two people arrested on suspicion of her murder.

Nathan Matthews, 28, and his partner Shauna Phillips, 21, are still being questioned by police who were granted an extra 24 hours to keep them in custody yesterday.

Mr Matthews is the son of Becky's stepmother Anjie Galsworthy, the Daily Mirror reported, and the couple are believed to have a two-year-old daughter.

A photo from 2012 believed to show Nathan Matthews, 28, and his partner Shauna Phillips, 21

Avon and Somerset Constabulary said that Ms Phillips was taken to hospital overnight after feeling unwell in custody but returned after seeing a doctor.

Five other people, four men and a woman all aged in their 20s, were arrested on suspicion of assisting an offender after the 16-year-old's body parts were found at a house two miles from her family home.

Police were awarded an additional day to question the five by a judge at Bristol Magistrates' Court earlier today and they are still being held in custody.

Shauna Phillips, the girlfriend of Becky Watts' step-brother Nathan Matthews (Facebook)

Officers found Becky's remains in Bristol after receiving a tip-off on Monday night, more than 10 days after she went missing, telling them her body had been “cut up” and where to find it.

Becky’s family spoke of their devastation when the grim discovery was announced after hundreds of volunteers joined police in huge search efforts and a social media campaign for information on her disappearance reached four million people.

Her mother, Tania, grandmother Pat and brother Daniel Watts, said they were “devastated”.

“We are at an utter loss to understand why anyone would want to hurt our beautiful Becky in such a brutal way,” they added, confirming that no one in custody was connected to their family.

Becky's father, Darren Galsworthy, and step-mother Mrs Galsworthy said the news the teenager was dead was “too much to bear”, pleading for privacy.

“We are heartbroken…we cannot begin to understand what has happened and why,” her grandfather John Galsworthy added.

“Becky was a wonderful daughter, sister, granddaughter and niece, and we cannot put into words how devastated we are.”

Becky's brother, Dan Galsworthy, wrote on Facebook: "Can't believe what I'm hearing...this has left a deep hole in my heart and will continue to haunt me."

Detective Superintendent Mike Courtiour, of Avon and Somerset Police, said police had received “new information” late on Monday night that led them to her remains, although they have not yet been formally identified.

Police continue their investigations outside properties in Barton Court on March 3 (Getty)

The teenager, described by her family as "shy", vanished from her home in Crown Hill on 19 February and was reported missing the next day.

She had taken her phone, laptop and tablet computer but did not tell friends or family where she was going or take extra clothes.

Flowers are left outside Becky Watts' family home on 3 March (Getty)

Flowers and tributes have been piling up near where her remains were found and at the gates of her home, where her family visited to lay their own bouquets in emotional scenes earlier today.