Police hunting for missing nightclubber Sian O'Callaghan said tonight they had found her body and that of another murder victim.
Detective Superintendent Steve Fulcher, leading the murder inquiry, said a 47-year-old man had been arrested on suspicion of two murders and kidnap.
The news came hours after police seized a green taxi which was seen early on Saturday when Miss O'Callaghan, 22, disappeared after leaving a nightclub in Swindon.
The Toyota Avensis estate with taxi markings was seen between 3am and 4am and 12pm to 9pm on Saturday between Swindon and Savernake Forest where police have been searching.
At a press conference tonight Mr Fulcher said: "A 47-year-old man from Swindon is in custody, having been arrested for kidnap and two murders.
"The location of two bodies have been identified to me by this individual, one of whom has yet to be identified formally, but I am quite clear is Sian.
"I have informed Sian's family, who are obviously deeply distressed, and I would ask you please to give them time and space to come to terms with what's happened.
"The public and the media have been a fantastic help in the desperate effort to find Sian over the last few days. This has of course been a fast-paced inquiry.
"Having found these bodies, you will appreciate that I am under extreme pressure to undertake certain actions and procedures, and I would ask you to give me some time to enable me to recover these bodies, with the dignity and respect that they deserve."
He said he was concerned for the family, and the effect this would have on them.
"I want to recover these people and give them the dignity they deserve."
Police reportedly arrested the suspect outside an Asda supermarket in Swindon. A green Toyota was also taken away on the back of a trailer.
Meanwhile, police began searching a house in Ashbury Avenue, Swindon.
Neighbours said the man who lived there was a cabbie who drove a green taxi.
A white police tent was erected in the front garden of the semi-detached house, which was cordoned off and had three police vans parked outside.
Specialist dog teams were drafted in today to help in the search for Miss O'Callaghan after mobile phone technology pinpointed several areas of interest in the 4,500-acre forest.
Police revealed earlier this week that phone records put Miss O'Callaghan's mobile somewhere in the forest 34 minutes after she left Suju nightclub at 2.52am on Saturday. It was a journey that could only have been made by car, police said.
Miss O'Callaghan, an office administrator, was caught on CCTV leaving the nightclub, in Swindon's Old Town area, after an evening out with girl friends.
She lived in a flat just half a mile away with her boyfriend Kevin Reape, 25.
Miss O'Callaghan's family today thanked members of the public who have helped in the search for "our beautiful girl".
Hundreds of people - many who did not know Miss O'Callaghan - have joined police searches of Savernake Forest, near Marlborough, or have put up posters appealing for help.
"We have been so touched by the support shown by the community that we wanted to express our thanks," the family said in a statement released by Wiltshire Police.
"The sheer numbers of people who have given up their time to help search for Sian and distribute appeal posters are overwhelming and we couldn't ask for better support from the public, police and media."
On Monday, Miss O'Callaghan's boyfriend made a tearful appeal for information.
Mr Reape, a quantity surveyor, was supported by his girlfriend's family, including her parents Mick, 51, and Elaine, 48, brother Liam, 24, and sister Lora, 19.
Fighting back tears, Mr Reape said: "We all want to know where Sian is and we want her home safe and well."
Mr Reape, who spent the day at Cheltenham races, raised the alarm at 9.45am on Saturday when she had not returned to their flat.