[5] They stated that the time that elapsed between O'Callaghan's appearance on the club's CCTV and her mobile phone signal (02:52 and 03:24 respectively) meant that the journey from Swindon to the forest could only have been made in a vehicle.

[5] On 23 March, police announced that analysis of O'Callaghan's mobile phone signals led to the identification of a number of "hot spots" to be investigated.

Detective Superintendent Stephen Fulcher of Wiltshire Police said that the investigation was moving at a "rapid pace", and that "significant lines of inquiry" were being developed.

[5] On 24 March, police made an urgent appeal for witnesses of a green Toyota Avensis with taxi markings, which had been seen between Swindon and Savernake Forest shortly after O'Callaghan's disappearance.

[7] On 1 April, the inquest at Oxford coroner's court was told that it was likely O'Callaghan died from head injuries, though a forensic pathologist from the Home Office had yet to confirm a precise cause of death.

[6] On 31 May 2012, taxi driver Christopher Halliwell appeared in court at a plea and case management hearing, and pleaded not guilty to the charge of murdering Sian O'Callaghan.

Justice Laura Cox ruled that Halliwell's confessions to killing each of the women were inadmissible as evidence, as Detective Superintendent Stephen Fulcher had breached the guidelines of the Police and Criminal Evidence Act 1984 by failing to caution Halliwell and denying him access to a solicitor during the period that the confessions were obtained.

[33] In lead detective Stephen Fulcher's 2017 book on the O'Callaghan and Godden-Edwards cases, he wrote that after apprehending Halliwell he had ordered the re-opening of the investigation into the unsolved 1995 disappearance of sex worker Sally Ann John, believing he may have murdered her.

[35] In 2015, police searched Sally Ann John's last-known address in Kimmeridge Close in Swindon, and days later arrested three men, aged 52, 50 and 52, on suspicion of her kidnap and murder.

[36] Detectives stated that they had liaised with the investigators on the Halliwell case but they were keeping an "open mind" on press reports claiming he may have been involved.

[36] John's mother revealed that her daughter had started to get involved with the "wrong people" in her late teens, and continued to associate with them despite warnings that they were bad characters, although shortly before she disappeared she had planned to try and get away from the life of sex work.

[44][45] In regard to Halliwell's possible involvement, Lawrence's mother stated "The police may not have proved he had anything to do with my daughter's disappearance, but they haven't disproved it either".