A former handyman accused of murdering a sixth former who disappeared 18 years ago is a convicted child killer already serving a life sentence, a court heard today.
Peter Tobin - who denies murdering 18-year-old Dinah McNicol who vanished in August 1991 - had already been convicted of killing 15-year-old Vicky Hamilton, a jury at Chelmsford Crown Court was told.
Miss McNicol, of Tillingham, Essex, disappeared after leaving a music festival in Liphook, Hampshire.
Jurors were told how detectives found her remains in November 2007 buried in the garden of a house in Margate, Kent, where Tobin lived in the early 1990s.
Prosecutor William Clegg QC said Miss McNicol's body was found wrapped in a bin bag a few yards from another grave containing Vicky's remains.
He told jurors that Tobin, 63, who comes from Johnstone, Renfrewshire, had been convicted of Vicky's murder and was serving a life sentence.
Mr Clegg said Vicky vanished from Bathgate, near Edinburgh, in February 1991.
He said Tobin had also been convicted of sexually assaulting two 14-year-old girls in 1994.
Mr Clegg said Tobin had administered the drug Amitriptyline - which makes people drowsy - to the two girls.
Post mortem checks had revealed traces of the same drug in the remains of Miss McNicol and Vicky.
Tests also showed that Miss McNicol had probably strangled with a ligature.
Forensic experts also found Tobin's fingerprints on the plastic bag used to wrap Miss McNicol's remains, said Mr Clegg.
Jurors were told that a neighbour had seen Tobin digging a hole - Miss McNicol's grave - and made a joke about "digging to Australia".
Prosecutors said Miss McNicol had met a man - David Tremlett now 45, and living in Llanberis, Caernarfon - at the festival and the pair had left together and started hitchhiking.
Mr Clegg said they had been picked up by a man matching Tobin's age and colour and Mr Tremlett had been dropped off near Redhill, Surrey.
Miss McNicol was never seen alive again.
The hearing continues tomorrow.