Detectives hunting for missing nightclubber Sian O'Callaghan are holding a man on suspicion of kidnap and two murders after revealing they have found her body.
Police said they know the location of a second body and are searching in a country area near the famous "White Horse" chalk figure at Uffington in Oxfordshire.
Officers have broken the news to Miss O'Callaghan's "deeply distressed" family that the 22-year-old is dead.
The arrest of a 47-year-old man came hours after police seized a green taxi which was seen early on Saturday when Miss O'Callaghan disappeared after leaving a nightclub in Swindon, Wiltshire.
Detective Superintendent Steve Fulcher told reporters: "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."
He also asked the media for time "to enable me to recover these bodies, with the dignity and respect that they deserve".
A Toyota Avensis estate with taxi markings was seen between 3am and 4am and 12pm to 9pm on Saturday between Swindon and Savernake Forest, near Marlborough, where police have also been searching.
Police reportedly arrested the suspect outside an Asda supermarket in Swindon. A green Toyota was also taken away on the back of a trailer.
Officers began searching a house in the town's Ashbury Avenue. 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.