The fatal wound inflicted on Owen Dunn was so severe that ‘no highly skilled surgeon’ could have saved him, a pathologist has said.

The Swindon teen was just two weeks away from turning 19 when he was stabbed to death on Mazurek Way, North Swindon on December 4 last year.

Two other local teenagers, Tyler Hunt, 18, and a 15-year-old who cannot be named for legal reasons, stand individually accused of murder or manslaughter. Their trial has been underway since November 14.

Giving evidence at Bristol Crown Court, Dr Basil Purdue revealed the findings of the post-mortem he performed on Owen.

Computer-generated images shown to the court documented several minor injuries that Owen had suffered, most of which are believed to have been caused during his fall after being stabbed and the resulting first aid attempt to save his life.

But the major wound discussed was a single stab wound to the chest, which was also listed as the cause of death.

Dr Purdue said: “He had a single stab wound on the left side of his chest, a stab entry wound which has produced a slit in the skin, in keeping with some sort of knife.

“If you track the injury – the point of the machete runs downwards, goes backwards, from Owen Dunn’s left to his right and down towards the centre of the chest.”

The court heard how the weapon penetrated Owen’s chest between the fourth and fifth ribs, went through the inner margin of the left lung and then caused damage to the top of Owen’s heart, as well as cutting through an artery.

“The depth of the wound was 15cm long, so around six inches,” Dr Purdue explained.

He added: “Owen died because of this injury. He had catastrophic bleeding and the damage caused stopped the heart from being able to pump. The left lung would have collapsed as well and would not have been functioning properly.

“There would have been a rapid but not immediate collapse followed rapidly and inevitably by death.”

Dr Purdue concluded: “Most skilled surgical treatment could not have arrived in time to save his life, even if an ambulance had been on hand it’s too big and bad an injury to put right.”

The court has heard how the accused travelled through Swindon in the hour before Owen’s death and appeared to be "looking for someone" while at the same time Owen was on his way to visit his girlfriend.

Witnesses in Mazurek Way at the time of the stabbing say Hunt and the 15-year-old laid in wait for Owen before ambushing him, with the younger of the two and then making the fatal blow with a machete.

Owen is said to have made his way on his bike where he crashed into a bollard and fell to the floor

CCTV footage capturing the moment was shown in court, followed by Ring doorbell footage displaying a loud ‘crash’ caused by Owen’s fall.  

The court heard a 999 call where a member of the public was asked by the call handler if the patient was breathing. They replied: “No he’s not. He’s passed away his eyes are open, he’s not breathing, he’s not breathing anymore.”

Both Hunt and the 15-year-old have admitted their involvement in Owen’s death but say that they were acting in self-defence and are not guilty of murder or manslaughter.

The trial is expected to continue for several more days and could last up to three weeks from its starting date.