A murderer offered police "another one" before leading them to a remote field where he had buried a sex worker he killed years earlier, a court in England has heard.
Christopher Halliwell, 52, allegedly told a detective he was a "sick f*****" as he confessed to strangling missing sex worker Becky Godden, 20, more than a decade ago.
The taxi driver was at that point under arrest for kidnapping Sian O'Callaghan, who had disappeared after leaving a nightclub in Swindon, Wiltshire, in March 2011, Bristol Crown Court was told.
Miss O'Callaghan's semi-naked body was discovered in undergrowth in Uffington, Oxfordshire, while the remains of Miss Godden were found in Eastleach, Gloucestershire.
Jurors heard that, while in Uffington, Halliwell told Detective Superintendent Steve Fulcher, who was leading the investigation for Wiltshire Police, simply: "We need to have a chat."
Halliwell allegedly went on to tell him: "I am a sick f*****. Is it too late to get help?"
He is said to have informed Mr Fulcher that he would show him the "exact spot" where Miss Godden's body was buried in a shallow grave, adding: "I know you are not a psychiatrist but what the f***'s wrong? Normal people don't go round killing each other."
It is alleged that Halliwell confessed to taking Miss Godden from the streets of Swindon at some point between 2003 and 2005 and strangling her after having sex with her.
The court heard that he then directed officers to Oxo Bottom field in Eastleach, where the skeletal remains of Miss Godden - later identified by DNA - were discovered.
Halliwell, formerly of Ashbury Avenue, Swindon, denies murdering Miss Godden between January 1 2003 and March 30 2008.
Nicholas Haggan QC, prosecuting, told the jury of six men and six women that Halliwell was serving a life sentence with a minimum term of 25 years after admitting the murder of Miss O'Callaghan.
But he claimed there was "no doubt of any sort" that Halliwell was also responsible for the murder and burial of Miss Godden.
"Her naked body was buried in a clandestine grave in a field which might be described as in the middle of nowhere," he said.
"You might conclude that it was plain Rebecca was murdered.
"But secondly, this defendant, Christopher Halliwell, confessed to the police that between 2003 and 2005 - he couldn't be sure of the date - he had taken a girl from the streets of Swindon.
"He told the police he had sex with her and then he killed her by strangling her. He told the police he stripped the girl of her clothes and concealed her naked body.
"Not only that but the defendant took the police to the location. Had the defendant not told the police where he had buried that girl from the streets of Swindon, you might think that Rebecca's remains to this day would be in that field in the middle of nowhere."
The court heard that the "last reliable sighting" of Miss Godden was in Swindon town centre in January 2003, possibly January 3.
"After that nothing more was heard from her. She made no contact with her family; she made no contact with any of the government and other agencies and financial institutions," Mr Haggan said.
"She quite literally disappeared. She was just 20 years old."
The court heard that she had started using Class A drugs and became a sex worker in her mid-teens operating in the Manchester Road area of Swindon.
Despite her lifestyle, Miss Godden - known as Becky or Rebecca to friends and family - kept in contact with her family, especially on Mother's Day and her birthday on April 4.
Karen Edwards last saw her daughter on December 16 2002, when she collected her following an appearance at Swindon Magistrates' Court and drove her to a friend's house in the town, the court heard.
A community beat officer recorded seeing Miss Godden on December 27 in 2002.
Rebecca Boast, a friend of Miss Godden, spent time with Becky outside a nightclub called Destiny And Desire in Swindon in early January 2003.
A taxi pulled up and Miss Godden approached it, returning to the car a short while later and arguing with the driver, Mr Haggan said.
"A short time later, Becky told her friends that she was leaving and she went back to the taxi," he told the jury.
"She got into the rear of the vehicle and the vehicle drove away. Rebecca Boast never saw her friend again, although she looked for Rebecca when she was out and about in Swindon town centre.
"Extensive inquiries by the police indicate that this probably was the last known reliable sighting of Becky."
The court heard that Miss Godden did not make contact with her family on Mother's Day in 2003, nor on her 21st birthday in April that year.
Halliwell, wearing a dark grey suit, white shirt and light blue tie, carried his own bundle of documents into the dock. During the trial he is defending himself.
Relatives of Miss Godden and Miss O'Callaghan sat in the public gallery.
Mrs Edwards, her partner, Charlie, and Miss Godden's father, John Godden, listened to proceedings.
Also present was Miss O'Callaghan's boyfriend, Kevin Reape, and her mother, Elaine Pickford.
Retired High Court judge Sir John Griffith Williams told jurors they should not assume that Halliwell's conviction for murdering Miss O'Callaghan made him guilty of killing Miss Godden.
"The prosecution case against Mr Halliwell, which will be developed this afternoon, is that there are similarities between the circumstances of the killing of Sian O'Callaghan and the killing of Becky Godden," the judge said.
"The prosecution case is that these similarities are such that they prove the defendant was the killer of Rebecca or Becky Godden.
"That is one of the issues in the case and you will have to decide, on the evidence as you hear it, whether there are such similarities and whether that inference can be drawn from those similarities.
"What you must not do is assume or conclude from the fact that he has pleaded guilty to the murder of Sian O'Callaghan. That would be wholly wrong."