A man remains in police custody suspected of killing nightclubber Sian O'Callaghan as police continue the search for a second murder victim.
Painstaking new searches have been launched after detectives said that a man suspected of killing Miss O'Callaghan gave them new information on the whereabouts of another murder victim.
The fresh forensic effort was sparked as the suspect reportedly told police where to find the remains of a second missing person. Detectives believe searches on the Oxfordshire-Gloucestershire border will lead them to Wiltshire's "one outstanding" missing person.
Detective Superintendent Steve Fulcher said the person had gone missing "several years ago" as search teams sifted land at Baxter's Farm, between the villages of Eastleach and Filkins.
Police refused to comment on speculation the remains they were looking for could belong to 39-year-old Tina Pryer. The mother of three was last seen getting in a taxi in Trowbridge in April 2001.
The suspect, named locally as taxi driver Christopher Halliwell, appeared before Swindon magistrates on Friday afternoon as officers were granted another 24 hours to quiz him.
Mr Fulcher, who is leading the inquiry for Wiltshire Police, said he had been personally taken by the suspect to the location where Miss O'Callaghan's body was found and where the search had begun for a second victim.
Police said they would not speculate on the identity of the person they were looking for. According to the Missing People website, the only Wiltshire missing person is a man called Anthony Fryer, who is 53 and has not been seen in Swindon since 2005.
Cases where no body has been found include college worker Linda Razzell, 41, who disappeared from Swindon in 2002. Her husband, Glyn, was convicted of her killing but protests his innocence.
Across the border in Gloucestershire, the body of Kate Prout has never been found after she went missing from her farm in 2007. Her husband, Adrian, was found guilty of her murder last year.