A convicted killer has been found guilty of murdering Becky Godden, whose body was found in a shallow grave in 2011.
Christopher Halliwell, a taxi driver from Swindon, killed the 20-year-old at some point between 2003 and 2005.
The 52-year-old laughed and smiled as the verdict was returned by the jury, and he will be sentenced on Friday.
Judge Sir John Griffith Williams said he was considering either a whole life order or a "significant" minimum jail term for Halliwell.
Miss Godden's mother, Karen Edwards, broke down outside Bristol Crown Court after the verdict was delivered, and said: "It has been a painful journey but today we have received the justice that has felt like an eternity coming for our beautiful little girl Becky.
"My message to any family out there who have waited so long for justice, as we have, is to never give up hope."
Miss Godden had turned to sex work to fund a drug habit and police believe Halliwell was a client who had become possessive.
She was reported missing in 2007 but was last seen alive in January 2003.
Halliwell is already serving a life sentence in prison for the murder of Sian O'Callaghan, who went missing in March 2011 after being seen on CCTV leaving a nightclub in Swindon and getting into Halliwell's taxi.
Days later, Halliwell was arrested on suspicion of kidnap and he led officers to a field in Uffington, Oxfordshire, where he had dumped the 22-year-old's body.
He then took the detective leading the case, Steve Fulcher, to a field in Eastleach where he said he had buried Miss Godden's naked body years before.
At the time, Halliwell had initially confessed to strangling Miss Godden, but the confession was ruled as inadmissible in court in 2012 because Mr Fulcher broke arrest guidelines and refused Halliwell's requests for a solicitor.
In a statement after the verdict, the detective defended his actions, saying: "Halliwell is an evil and depraved violator of women. I caught a serial killer, preventing any further girls being murdered."
Mr Fulcher resigned from Wiltshire Police in 2014, months after being given a final written warning for gross misconduct.
The trial of Halliwell for the murder of Miss Godden, which has lasted two weeks, saw the killer represent himself in court.
He claimed he had never met Miss Godden and that two drug dealers were responsible for burying her body.
He said he drove two men, who he refused to identify, to Oxo Bottom field after they told him "something went wrong".
Months later, he claimed they told him they had buried a prostitute from Swindon.
In summing up the case, the judge described Halliwell as a "liar whose word should be taken in some instances with a pinch of salt".
A friend of Miss Godden's, Rebecca Boast, said she last saw her getting into a taxi outside Destiny and Desire nightclub in Swindon in January 2003.
Halliwell called the RAC after running out of fuel in the early hours of 3 January 2003 near Highworth, close to Eastleach.
Later that day, he visited his GP with a broken finger and scratches to his face.
Soil samples found on a shovel in Halliwell's garden shed also matched those taken from the grave site where Miss Godden's remains were found.
Miss Godden's father, John Godden, told Sky News he wants his daughter to be remembered as the "wonderful, caring human being she was".