Vicky Hamilton may have fought for her life despite being drugged and pinned down on a floor, a jury heard yesterday.

The High Court in Dundee has been told how marks on the teenager's body might be clues to her final agony. She may also have been subjected to a serious sexual assault, it is alleged.

The marks on her back, chest, neck and hand were revealed during post-mortem examinations carried out almost 17 years after she disappeared on her way home to Redding, Falkirk.

The trial has heard how pathologist Dr David Rouse performed the first autopsy after Vicky's severed body was dug up from a back garden in Margate, Kent. He said a possible cause of death was "compression of the neck".

Yesterday the trial heard further revelations from a second post-mortem carried out in Edinburgh on November 20 last year by Professor Anthony Busuttil and a colleague. The professor said it had not been possible to ascertain a cause of death.

"We can exclude things but we cannot point a finger to a particular mode or method of death," he said.

But he found a bruise to Vicky's right hand as well as a further bruise about the size of his hand to the right side of her chest and another to the left side of her back.

"These suggest a violent episode very close to the time of death," said Mr Busuttil's post-mortem examination report. The mark to the right hand was the sort caused when someone tried to protect their face by grabbing a weapon - or even a fist, he told the trial.

Solicitor general Frank Mulholland, QC, prosecuting, suggested a possible scenario to Mr Busuttil.

"Vicky is on the floor. Someone has their knee or leg on her chest. Her neck is being compressed by the other person. She tries to defend herself, to stop this happening. Her right hand is free.

"The person who is doing this, when Vicky tries to defend herself with her right hand strikes her right hand and continues to press the neck.

"Are these injuries, bruises, consistent with the hypothesis I have just put to you?"

Mr Busuttil agreed they were.

Mr Mulholland then asked about the drug amitriptyline which later tests had revealed were found in 15-year-old Vicky's body and asked the professor about their effects.

The pathologist told him: "If these were taken for the first time, or in large doses, they may cause confusion. You don't know where you are. They may cause disorientation or may cause you to lose consciousness entirely."

The trial has heard that amitriptyline, an anti-depressant drug, was prescribed to Peter Tobin, 62, - who denies abducting and murdering Vicky and burying her body parts. Vicky vanished from Bathgate, West Lothian, on February 10, 1991.

Donald Findlay, QC, defending Mr Tobin, challenged Mr Busuttil's findings. The professor agreed that, although the marks on the teenager's body looked like bruises to the naked eye, he could offer no scientific evidence to back this up, unlike the definite bruise to her hand.

The trial continues.