Police investigating the murder of PA Sian O'Callaghan are today working to identify human remains found in a field as they continued to question a man.

Officers found the remains on Saturday following extensive searches at a site near Eastleach, on the boundary of Oxfordshire and Gloucestershire.

Det Supt Steve Fulcher said the team from Wiltshire Police had been told they were those of a woman abducted in Swindon between 2003 and 2005.

He also revealed that an examination of 22-year-old Miss O'Callaghan's body, which was found near Uffington on Thursday, revealed she had not been sexually assaulted. Miss O'Callaghan's body was formally identified by her family on Friday night.

Speaking at a press conference in Swindon, Mr Fulcher said: "This morning officers have found remains which we believe to be human at the site at Eastleach."

He also said that while the 47-year-old man being held in connection with the two murder investigations had told them when a victim was abducted, he gave no indication of an exact time and date, or her identity.

"He indicated he killed a young woman between 2003 and 2005. He could not be specific about the date but he said she had been taken from the Swindon area."

Mr Fulcher also made a public appeal for anyone "lamping or poaching" in the area around Ramsbury, near Marlborough, in the early hours of Saturday last week, hours after Miss O'Callaghan disappeared, to contact police without fear of arrest over their illegal activities.

News that the remains of a second person had been found came hours after police were granted a further extension by magistrates in Swindon to hold the man being questioned in connection with Miss O'Callaghan's death. The suspect being held has been named locally as taxi driver Christopher Halliwell.

A lantern vigil in Miss O'Callaghan's memory was held at Swindon's Polo Ground last night.

Thousands of people gathered to remember at the vigil on the day police found human remains at a field they are searching in Gloucestershire.

Hundred of Chinese lanterns and balloons were launched into the night sky and a two-minute silence was held at 8pm as part of the Lighting Up The Sky for Sian gathering. The event had been arranged when 22-year-old Sian was still officially missing, before her body was found on Thursday.

A message posted on the Lighting Up The Sky for Sian Facebook page read: "In light of the recent tragic news of the discovery of a body Police believe to be Sian's, we see it fit to change the purpose of this gathering."

Wiltshire Police said hundreds of floral tributes to Miss O'Callaghan, which were placed outside the Suju nightclub where she had spent the evening before her disappearance with friends, would be removed to allow it to reopen.