The only chance of survival for a man stabbed in the heart with a 10-centimetre knife would have been if the blade had stayed lodged in his chest, a murder trial jury has been told.

A 16-year-old and a 14-year-old are standing trial in the High Court in Hamilton, accused of murdering Norman Kingi, 54, who died following the incident in Rānui Street in Dinsdale about 11.30pm on Friday, July 28 last year.

The Crown case against the pair alleges they were the elder two of three girls - at the time aged 15, 13 and 12 - who were caught in the act of breaking into a Nissan Primera owned by Kingi and his partner Vicki-Lee Reihana, which was parked on the roadside outside their house.

The couple apprehended the youngest girl, while two others ran off - only to return soon after armed with a knife and a screwdriver respectively.

There was a confrontation and it is alleged the oldest girl, who had the knife, stabbed Kingi in the heart, fatally injuring him.

On Wednesday afternoon the jury heard evidence from Dr Simon Stables, a forensic pathologist who performed an autopsy on Kingi the following day.

Stables said Kingi had died from a single stab wound that penetrated 10 centimetres into his chest, puncturing the right ventricle of his heart.

The injury was not survivable and he would have been dead within minutes.

The only way he could have lived - and it was a slim chance - was if the knife had been kept in his chest and he had immediately been rushed to hospital for surgery, Stables said.

As the jury heard earlier in the trial, the knife that inflicted the fatal wound was found the following day, stashed in the bottom of a bin in a toilet in the Hamilton Police Station.

Under cross examination from Ron Mansfield, the defense lawyer for the older girl, Stables also revealed that Kingi had a lot of alcohol in his system when he died.

Tests showed he had a blood alcohol reading of 138 milligrams of alcohol per 100 millilitres of blood.

Mansfield made the observation for comparison purposes that the legal driving level is 50 milligrams of blood.

Stables said he estimated that the level of alcohol indicated Kingi would have consumed around eight standard drinks beforehand.

The court also heard from Anna Lemalu, a DNA analyst from Environmental Science and Research (ESR)

She had scrutinised samples of blood taken from the knife used to kill Kingi and from a sweatshirt that had been worn by the oldest girl at the time of the incident.

Using the ESR's system of determining the origins of that blood, she had calculated it was one hundred thousand million times more likely that the blood on the sweatshirt was from Kingi and one other person, than from two New Zealanders selected at random.

The blood sample taken from the knife was two hundred thousand million times more likely to come from Kingi and one other person.

Due to their young age, the two accused have interim name suppression until the conclusion of the trial, at which point a final decision will be made on whether they can be named.

Mansfield is acting for the 16-year-old, while Roger Laybourn is counsel for the 14-year-old.

The Crown case is being handled by Philip Morgan QC with assistance from Shelley Gilbert.

The trial, before Justice Timothy Brewer, began on Monday and has been estimated to run for two weeks.

-Stuff/Mike Mather.