A man has been arrested on suspicion of the kidnap of Sian O'Callaghan, who disappeared after leaving a nightclub in Swindon on Saturday.
Miss O'Callaghan, 22, has not been seen since she left the town's Suju nightclub in the early hours.
The man was held at a supermarket in north Swindon where police also seized a green Toyota car.
Police confirmed a number of locations across the county were also being searched as part of the inquiry.
Ch Supt Steve Hedley, of Wiltshire Police, said: "A short time ago a man was arrested on suspicion of the kidnap of Sian O'Callaghan and is en route to a police custody centre.
"Sian's family have been informed.
"It is a significant stage in this difficult inquiry. Our priority is to find Sian and we are doing all that we can to do so.
"Further information will be released in due course but it is not appropriate for me to make any further comment at this time."
On Thursday afternoon a white tent was put up outside a semi-detached house in Ashbury Avenue, near Greenbridge, in Swindon.
A Wiltshire Police spokeswoman would not comment on its significance but confirmed a number of locations were being examined.
BBC correspondent Robert Hall, who is at the scene, said the house is occupied by a man in his mid 40s and neighbours say the taxi is often on the drive.
"Forensic officers are searching the inside and the outside of the property and items brought out and put into a police van," he said.
Detectives are also searching a second location between Ashbury and Letcombe Regis, some seven miles east of Swindon, and close to the Uffington White Horse, Oxfordshire.
Officers had earlier appealed for sightings of a green Toyota Avensis estate with taxi markings, seen between Swindon and Savernake Forest, near Marlborough, shortly after Miss O'Callaghan was last seen.
Specialist dog teams were drafted in to help in the search for the office administrator on Thursday after detectives using mobile phone technology pinpointed several areas of interest in the 4,500-acre forest.
Police are also appealing for information about items believed to have been in Miss O'Callaghan's handbag.
The bag is described as large and dark, with a beige flower on the side.
A spokesman said she was likely to have had items similar to a front door key with a "distinctive pattern", a black car key with yellow insulation tape, a Tesco Clubcard key fob, lip gloss and a yellow Kinder Egg plastic casing containing an orangey-brown squirrel with a felt belly.
He said she was also believed to have worn or had with her a DKNY watch with false diamonds and had been wearing a pair of brown boots.
About 200 people attended a vigil for Miss O'Callaghan on Wednesday night.
An area of the road and the verge has been sealed-off and is being guarded by a number of police officers.
A reward to help find her now stands at £40,000.
In a statement, Miss O'Callaghan's family said: "We have been so touched by the support shown by the community that we wanted to express our thanks.
"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.
"We are aware of the reward that has been offered and are very grateful; we hope that this might help someone come forward with information to help the police find her.
"This is an extremely difficult time for us and we continue to hope and pray that our beautiful girl is found soon."
http://www.bbc.co.uk/news/uk-england-12845965
