The family of missing teenager Rebecca Watts say they are "prepared for the worst" as searches for the quiet 16-year-old continue.
Avon and Somerset Police this afternoon arrested two people in connection with the disappearance of the youngster, also known as Becky.
It came after more than 100 people gathered to conduct their own search of land in the Fishponds area of Bristol near where Becky lived, during which part of a laptop was discovered and handed to murder probe detectives.
Becky's father Darren Galsworthy and step-mother Anjie-Mae Galsworthy said: "We continue to hope that she will be found safe and unharmed but we will prepare ourselves for the worst."
In a statement, the couple said: "We would like to take this opportunity to thank everyone who has assisted in the search for Becky and for the messages of support.
"We continue to work with the police to bring their investigation to a successful conclusion and we would like to ask members of the public to continue to report anything, however small, if they think it may help to find Becky."
Mr Galsworthy and his wife have been informed of the double arrest tonight, police said.
Avon and Somerset Police Detective Superintendent Liz Tunks, who is leading the investigation, said: "Whilst the two people are being questioned our search for Becky continues unabated.
"I would like to appeal once again for anyone who might have information about her whereabouts, or anything else that might help us to find her, to call us."
It has been more than a week since the teenager was last seen at her house in Crown Hill in the St George area of Bristol.
She left home on February 19 with her phone, laptop and tablet computer but did not inform friends or family where she was going, or take extra clothes.
Avon and Somerset Police have been searching for the teenager, described as shy, since she was reported missing by her family at 4pm on February 20.
Police divers have been carrying out open water searches on the lake in St George's Park, which is close to Becky's home, while police from neighbouring force areas have also been drafted in to help.
An online campaign for the teenager was launched by police earlier this week, using the hashtag #FindBecky.
Becky is described as 5ft 4in and slim, with long, bright red hair and was wearing a dark navy blue Puffa jacket with fabric sleeves.
Anyone with information is asked to contact Avon and Somerset Police on 101, or Crimestoppers on 0800 555 111.