Did stepbrother hack Becky to pieces?

Murdered ... Becky Watts, 16, vanished from her home on February 19. Picture: Supplied Source: Supplied

UK Police searching for missing Bristol teenager Becky Watts have found body parts at a property near her family home.

BECKY WATTS' stepbrother and his girlfriend are being questioned by police on suspicion of kidnapping and murdering the missing Bristol teenager.

Nathan Matthews, 28, and Shauna Phillips, 21, remain in custody after police discovered body parts at a Barton Court property in their hunt for the 16-year-old.

Detectives have been granted another 24 hours to question Matthews and Phillips, who were arrested on Saturday, The Telegraph in the UK reports. Police have until Wednesday afternoon to charge or release the pair.

BECKY WATTS SEARCH: Body parts found

Matthews is reportedly the son of Anjie Galsworthy who is married to Becky's dad, Darren Galsworthy. Matthews, a delivery driver, and Phillips have a two-year-old daughter.

Avon and Somerset Police are also questioning another four men and a woman, all in their 20s, on suspicion of assisting an offender.

Family ... Becky's relatives (from left): dad Darren Galsworthy, stepmother Anjie Galsworthy, stepbrother Nathan Matthews and girlfriend Shauna Phillips. Picture: Facebook/Darren Galsworthy Source: Supplied

Shauna Phillips is being questioned by police. Picture: Facebook/Shauna Phillips Source: Supplied

Police believe Becky Watts was murdered. Picture: Facebook/Help Find Missing Rebecca 'Becky' Watts Source: Supplied

Friends have expressed shock at the couple's arrest, saying they were just "normal people".

"She (Phillips) messaged me on the Friday and she asked me if I had seen Becky or I could help with the search," a friend, who has not been identified, told The Mirror.

"The police came to speak to me and as soon as they announced the ages I just knew it was them. She's just a normal person, they both are. There's no reason they could do it. I've been racking my brains but I just don't get it."

Phillips had posted many articles and shared heartfelt messages about Becky's disappearance on her Facebook page.

An acquaintance of Matthews, who did not want to be named, said he was "pleasant".

"I have spoken to police about Nathan. He is a very pleasant chap and I am surprised about his arrest. He is quite a reserved guy and has good discipline from his time in the Army," he told The Bristol Post.

Scene ... a police forensic tent is pitched outside a property in Barton Court on March 3. Picture: Matt Cardy/Getty Images Source: Getty Images

Well wishers have left floral tributes close to Becky's home in St George and the property in Barton Court where body parts, believed to be the teen's, were found.

Police said formal identification procedures of the body parts have not yet been completed.

Becky's family said they were devastated after hearing police found body parts.

"We are devastated to be told of this latest development. We are at an utter loss to understand why anyone would want to hurt our beautiful Becky in such a brutal way," the teenager's mother Tania Watts, brother Daniel and grandmother Pat said in a statement.

Becky's father and stepmother, Darren and Anjie Galsworthy, said: "To receive such news as we did about our dear daughter and stepdaughter Becky is too much to bear."

Search ... a police forensic team investigates a property in the Barton Hill area of the city as they continue to search for missing teenager Rebecca Watts on March 2. Picture: Matt Cardy/Getty Images Source: Getty Images

Becky's family reported her missing on February 20 after she left home with her phone, laptop and tablet computer, but no extra clothing.

After extensive searches, police announced on March 2 they were treating Becky's disappearance as a murder investigation.

A social media campaign, using the hashtag #FindBecky, has gained thousands of hits.