The stepbrother of 16-year-old Becky Watts has been charged with her murder, while his girlfriend has been charged with intending to pervert the course of justice.

Nathan Matthews, 28, and Shauna Hoare, 21, both of Cotton Mill Lane, Bristol, remain in police custody and will appear at Bristol Magistrates' Court tomorrow.

Four men and one woman arrested on suspicion of assisting an offender also remain in custody at this time, a spokesman for Avon and Somerset Police said.

Matthews and Hoare, who uses the surname Phillips on her social media accounts, were arrested on suspicion of Becky's kidnap on Saturday.

They were later rearrested on suspicion of her murder and detectives had until this afternoon to charge or release them.

A force spokesman said: "Nathan Matthews, 28, of Cotton Mill Lane, Bristol, has been charged with the murder of Rebecca Watts. He remains in custody and is due before Bristol Magistrates' Court tomorrow at 10am.

"Shauna Hoare, 21, of Cotton Mill Lane, Bristol, has been charged with intending to pervert the course of justice. She remains in custody and is due before Bristol Magistrates' Court tomorrow at 10am.

"The four men and one woman who were arrested on Monday on suspicion of assisting an offender remain in police custody at this time.

"A warrant of further detention was granted for these suspects at hearing earlier today."

Hoare was last night rushed to hospital by officers after "feeling unwell" in custody but returned after being seen by a doctor, police previously said.

Becky, described as "wonderful" by her family, vanished from her home in Crown Hill, Bristol at 11.15am on February 19.

Avon and Somerset Police launched a huge search operation - involving six police teams each day - after she was reported missing the following afternoon.

Wiltshire officers were among those drafted in to help.

On Monday night, detectives received information that Becky's body had been "cut up" and they attended a house in Barton Court, Barton Hill, Bristol.

Body parts were discovered at the address, which continues to be combed by forensics teams. A private ambulance was seen leaving the property yesterday afternoon.

Bouquets, teddies and cards have been left at the family home where Becky went missing, and at the site where body parts were found.

The five people arrested on suspicion of assisting an offender following the grim discovery are four men, aged 29, 29, 23 and 23, and one woman, also aged 23.

Matthews was identified as the teenager's stepbrother - the son of her father Darren's wife Anjie - by family members.

Formal identification procedures of the body parts has not yet been completed.

Churches, such as St Luke's in Barton Hill and St Ambrose near to Becky's home, have opened for mourners to pay their respects.

Rachael Scott, head of the CPS South West Complex Casework Unit said she had been offering "advice and guidance" to police since the arrest of Matthews and Hoare.

"Having carried out a detailed review of the evidence gathered by Avon and Somerset Police, my conclusion is that there is sufficient evidence to charge Nathan Matthews with the murder of Becky Watts," she said.

"I have also concluded that there is sufficient evidence to charge Shauna Hoare with attempting to pervert the course of justice.

"I have therefore today authorised Avon and Somerset police to charge them with these offences and they will appear before Bristol Magistrates' Court tomorrow morning.

"Proceedings are now ongoing and the defendants have the right to a fair trial.

"It is very important that there should be no reporting, commentary or sharing of information online which could in any way prejudice these proceedings."

In a post on Facebook, Becky's brother Dan Galsworthy wrote: "To everyone messaging and supporting me I haven't replied to any messages because I simply have no words, I thank you all and deeply appreciate everyone's support. Love to you all."

A heavy police presence remains in Barton Hill as uniformed officers continue fingertip searches of areas surrounding Barton Court and Cotton Mill Lane.

Writing on Facebook, aunt Sarah Broom said of Becky's father: "He is completely and utterly broken and there is nothing in this world of comfort to him - how does a parent ever recover from this? How can a family?

"So with tears rolling down my face, Becky, you beautiful beautiful soul, you have touched so many hearts and changed so many lives.

"Your shy inverted nature has outshone and touched a whole city and beyond.

"You do not leave behind a legacy of anything other than pure heartfelt love and you, you beautiful girl, will live on forever in the hearts of all those that have carried you in theirs the last 12 days and of course those that carried you in your lifetime."

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

The teenager's mother Tania Watts, brother Daniel and grandmother Pat said: "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."

They added that none of those in custody is "connected to the Watts family".

John Galsworthy, speaking on behalf of the Galsworthy family, said: "Becky was a wonderful daughter, sister, granddaughter and niece and we cannot put into words how devastated we are."

The search since Becky was officially reported missing on February 20 has involved a social media campaign which has reached more than four million people worldwide.

Tributes continued to build at Barton Court today, including a large collage with messages from friends and pictures of the teenager on it.

The Rt Rev Mike Hill, Bishop of Bristol, paid tribute to Becky's family and said he had been "deeply" affected by the death.

"I feel sure that people both of faith and of no faith will join with me in wishing to support the friends and family of Becky Watts in the light of the deeply shocking and unfolding news of her death," he said.

"They have acted with dignity throughout this awful nightmare since the day Becky went missing."