A pathologist has told jurors in the Emily Longley murder trial in Britain it is possible she was strangled using a method known as a sleeper hold.
The New Zealand teenager was found dead in her boyfriend's bed at the house he shared with his parents in Bournemouth last May.
Elliot Turner, 20, denies the charge of murder at his trial at Winchester Crown Court in Hampshire.
Dr Hugh White, who carried out the post-mortem on Ms Longley's body, told the trial tiny burst blood vessels in her eyelids were consistent with the throat being squeezed.
Dr White gave evidence that there were no injuries to Ms Longley's neck and if she was asphyxiated, she must have been rapidly incapacitated or restrained in some way.
A BBC correspondent reports that sleeper hold method of constricting a neck was demonstrated but that Dr White said the post mortem was inconclusive.