Sian's mobile calls from worried boyfriend were picked up by mobile masts at Bayden and Cadley in Savernake Forest.
Halliwell then moved Sian's body to copse near Uffington White Horse.
Sian's mother Elaine: 'I'm just a mum who wants her daughter back.'
The murder trial into the death of Sian O'Callaghan has ended, with the life imprisonment of her killer - taxi driver Christopher Halliwell.
Wiltshire Police have made a statement following the jailing for life of Christopher Halliwell for the murder of Sian O'Callaghan.