The mother of Becky Godden-Edwards has appealed for help in getting justice for her death.
It has emerged that a police blunder meant a charge relating to Becky, against taxi driver Christopher Halliwell, had to be withdrawn.
Karen Edwards said; "after a very complicated and painful journey over the last eighteen months, Sian's family have today had the justice for the murder of their beautiful daughter. However our families' fight for justice for Becky has only just begun.
"I would like the full support of you all to help me get justice for my daughter Becky."
The Independent Police Complaints Commission is to independently investigate breaches of the Police and Criminal Evidence Act in the investigation into the deaths of Rebecca Godden and Sian O'Callaghan:
Sian O'Callaghan's mother has spoken outside the court where taxi driver Christopher Halliwell was convicted of the murder of the 22-year old.
Elaine O'Callaghan said, "Our lives have been changed forever as the result of a truly wonderful life being taken too soon."
Wiltshire Police have expressed their sympathy for the family of Sian O'Callaghan and praised their, "great dignity throughout the court process."
In a statement the police said:
"This was a complex and fast moving investigation and from the outset the priority of the Senior Investigating Officer Detective Superintendent Steve Fulcher was always to try and find Sian alive but unfortunately this was not possible.
"This was a violent and brutal murder of a young woman in the prime of her life. It is likely that Sian suffered horrifically from the point that she was abducted.
"Halliwell, in committing this crime, betrayed his position of trust as a taxi driver as he preyed on a lone vulnerable female.
"Today’s hearing was about bringing justice for Sian’s family. They have continued to display great courage and dignity and we hope this will provide them with some comfort at this most difficult time."
Wiltshire Police said Detective Superintendent Steve Fulcher had been suspended pending an investigation by the Independent Police Complaints Commission into allegations of "inappropriate contact with the media".
Christopher Halliwell, who has admitted murdering nightclubber Sian O'Callaghan, has escaped justice over a second murder because of a police blunder, it can be reported today for the first time.
The second charge, involving Becky Godden-Edwards, was withdrawn after a High Court judge ruled that Detective Superintendent Steve Fulcher breached Halliwell's rights by failing to caution him and denying him a solicitor in an attempt to force information out of him.
Christopher Halliwell must serve a minimum sentence of 25 years for the murder of Sian O'Callaghan.
Taxi driver Christopher Halliwell was jailed for life today after he pleaded guilty to murdering nightclubber Sian O'Callaghan.
Father-of-three Halliwell, 48, of Ashbury Avenue, Swindon, pleaded guilty to the charge during a hearing at Bristol Crown Court.
Miss O'Callaghan, 22, disappeared after leaving Swindon's Suju nightclub in the early hours of March 19 last year after a night out with friends.
She left the club at 2.53am for the short walk to the home she shared with boyfriend Kevin Reape.
Shortly after she walked past the Goddard Arms on the High Street in the Old Town area, she fell into Halliwell's clutches by getting into his taxi.