Kiwi Emily Longley could have been strangled in a "sleeper hold" or suffocated with a pillow, medical witnesses have told a UK court.
A pathologist and medical expert have given evidence at Winchester Crown Court in the trial of Elliot Turner - the 20-year-old accused of strangling Longley in a jealous fit of rage.
Turner has pleaded not guilty to the murder of his girlfriend on May 7 last year at his parents' home in Bournemouth, South England.
Pathologist Dr Huw White, who conducted a post mortem examination on Longley's body, said it was possible the student and aspiring model was strangled but he could not be sure as he had found no external or internal injuries.
He told the jury the cause of her death was unascertained.
The post mortem examination found petechiae haemorrhages on the point of her right eye, in both her eyelids and one on the inner surface of her upper lip, the Bournemouth Echo reported.
"They are tiny little bleeds caused by rising blood pressure in the head," White said.
"Common causes are rising pressure in the chest or compression of the neck."
Under cross examination, White explained what he called a sleeper hold, when a person's neck is held against the softer inside of the arm to constrict breathing.
This method of strangulation pinches nerves in the neck which interfere with the victim's heart beat and does not necessarily produce any visible signs of internal or external injuries.
White's evidence was backed by forensic expert John Payne-James who said it was possible to exert pressure to the neck, causing strangulation, without leaving any visible marks.
He said Longley's pathology was "entirely consistent" with such pressure having been applied.
Payne-James also told the jury it could have been possible Longley was smothered with a pillow after she had passed out.
At the time of her death, Longley was moderately intoxicated, with a blood alcohol level twice the legal driving limit in the UK.
Her medical history, showing juvenile osteoporosis and episodes of bulimia and self-harm after her parents had separated a number of years ago, was discredited as a possible reason for her death.
Longley showed no signs to suggest a natural death, the court heard.
Scratches and bruises
Turner is also accused, together with his parents Leigh Turner, 54, and Anita Turner, 51, of perverting the course of justice. His parents deny the charges.
The court was also shown photos of Elliot Turner taken on the day Longley was found dead, showing scratches and bruises of his arms and torso.
These were described as "blunt contact" injuries by Payne-James but said he could not say what caused them.
Turner blamed the injuries on Longley saying he was only trying to defend himself when she had kicked him in the head.
He told police he had "sort of grabbed her by the neck with my right hand and just pushed her".
The trial is expected to last another three weeks.