SIAN O' Callaghan's mother has urged the public not to speculate about suspected victims of double murderer Christopher Halliwell.

Elaine Pickford, from Old Town, spoke out after suspicions were aroused that Halliwell may have committed more murders after his conviction for murdering Becky Godden last week.

Becky's mother Karen Edwards told the Mail on Sunday she believed Halliwell could be linked to the murders of Swindon women Sally Ann John and Linda Razzell as well as Melanie Hall and Claudia Lawrence.

In a statement Elaine said: "Having read a lot over the weekend in various newspapers and online I cannot help but feel there is too much speculation going on around Christopher Halliwell and suspected victims.

"Despite my belief that there is likely to have been more victims, I personally do not feel it is helpful to either the police or those families to publicly speculate on those victims, scenarios and to presume.

"Having been through the awful five day experience when Sian was missing, you are as a parent and a family imagine all sorts of things, as well as trying to retain some small hope. Public speculation I don't feel would have helped us, just facts which we were kept up to date on during those days and sadly when Sian was found.

"For parents and families of these missing women who continue to suffer must be dreadful, I do hope that anyone who is experiencing a missing loved one does have their questions answered by good police work and facts."

The lead detective in the Becky Godden murder inquiry said he was convinced Halliwell was a serial offender and that Wiltshire Police will pursue new lines of enquiry.

Detective Inspector Sean Memory, who spoke outside Bristol Crown Court following Halliwell's sentencing on Friday, said: "I am also very, very clear there must be other victims out there, whether they are sexual offences or other women that he has taken," Mr Memory said.

"I can't believe that was his first offence, from being a burglar in the 1980s to a murderer in 2003. There was a significant gap in his offending behaviour.

"On top of that, Sian wasn't murdered until 2011 so what happened in the interim eight years?

"He talked candidly in 1985 about wanting to be a serial killer and I genuinely believe that's a distinct possibility.

"I will now seek to review outstanding cases, I will appeal to Christopher Halliwell again to tell the truth for once in your life and come and speak to me."

A force spokesman said today: “Wiltshire Police made an unwavering commitment to the families concerned, and the public, in 2011 that justice would be served.

“Since this time, there has been a dedicated investigation team working on this case and it is down to the diligence and professionalism of that team, working closely with the Crown Prosecution Service, that we were able to bring Christopher Halliwell to a successful prosecution.

“We recognise there is an eight year gap between the murders of Becky Godden in 2003 and Sian O’Callaghan in 2011. From the early stages in this complicated investigation, it was conceivable that there may have been further victims of Christopher Halliwell either prior to Becky’s death or after it.

“This has always formed an important part of the senior investigating officers' approach and this has been a key aspect of the investigation throughout.

"We have therefore already engaged with a number of agencies in relation to Christopher Halliwell. The additional information we have learned about Halliwell's character during the court case, alongside the facts established regarding his modus operandi, will assist us going forward.

“Serious and major crime investigations are a complex aspect of policing. It remains our commitment to keep an open mind and follow the evidence wherever that may take us, so if there are further victims of Halliwell, then our investigation will work tirelessly to bring justice for all those concerned.

“To assist us in this, we strongly discourage speculation as this will cause further distress to families and friends of people who are currently missing across the country, who will clearly be desperate to have news of their loved ones.

“We would however welcome any new information from the public, or indeed, from Halliwell himself.

“Christopher Halliwell will no longer be a danger to the public following his whole life tariff sentence. Our thoughts remain with the families and friends of Sian and Becky who have shown great dignity and strength throughout.

“This has been a difficult, emotive and challenging time for all parties involved.

“We hope that they are all now able to find some closure following his sentencing.”