Double murderer: 'How many women do I need to kill to be serial killer?'
Double murderer Christopher Halliwell spoke of strangling a woman during sex and asked how many victims he would have to kill to become a serial killer.
The taxi driver had sex with Becky Godden, 20, then strangled her after becoming possessive of her and resenting her work as a prostitute in Swindon, Wiltshire.
He left her body in a hedge at Oxo Bottom field in Eastleach, Gloucestershire - later returning to bury her naked in the shallow grave where she lay undiscovered for eight years.
In March 2011, former groundworker Halliwell abducted office worker Sian O'Callaghan, 22, as she walked home from a night out in Swindon.
The father-of-three stabbed and strangled Miss O'Callaghan then dumped her body in a copse near Ramsbury, Wiltshire.
He twice returned to her body - cutting her underwear and leggings in an attempt to remove her clothing - and moved it to a ditch in Uffington, Oxfordshire.
Detective Superintendent Steve Fulcher, who brought Halliwell to justice for Miss O'Callaghan's murder, told Bristol Crown Court he believed there were other victims.
And following Halliwell's conviction for murdering Miss Godden, it can now be reported that he discussed strangulation and the definition of a serial killer with a fellow prisoner.
The jury was not told of the account of Ernest Springer, an inmate at HMP Dartmoor with Halliwell in 1986, when the killer was serving a sentence for burglary.
In a legal ruling about which evidence could be put before the jury, retired High Court judge Sir John Griffith Williams described what Springer claimed Halliwell said to him.
"The prosecution intends to rely on the following evidence... bad character evidence to prove the defendant's overtly aggressive conduct towards women and his computer searches on the internet for indecent and violent material (and) the evidence of Ernest Springer, with whom the defendant shared a cell at HMP Dartmoor in 1986, and that the defendant was angry and aggressive towards women and talked of having sex with a girl while strangling her and asked how many women one would have to kill to be a serial killer," the judge wrote in his ruling.
In April 2016, prosecutors served a notice to introduce bad character evidence against Halliwell, including his conviction for murdering Miss O'Callaghan.
"The prosecution particularised also miscellaneous bad character evidence of a number of witnesses who described the defendant behaving in a strange or aggressive manner towards women as well as the evidence of Ernest Springer, a fellow prisoner at HMP Dartmoor, who related the defendant's excessive anger and aggression towards women and the evidence of the defendant's computer which revealed an interest in a range of sexual activity, from adult sex to paedophilia and bestiality with some entries in the schedule of searches suggesting an interest in murder, violent sex and rape."