A teenage boy bled to death in the street after being stabbed through the heart and lung with a 13.5cm (5.3in) zombie knife in a frenzied attack, a court has heard.

Prosecutors allege Tristan Kerr, 17, from Abertridwr, Caerphilly, was attacked at a house in Lower Francis Street in February by Georgie Mears, 19, from Thornhill, Cardiff.

He denies murder, and is on trial at Newport Crown Court with Connor Palfrey, 24, from Abertridwr, Caerphilly, Ricardo Elliot, 27, of no fixed abode, and Elexi Manny, 24, from Senghenydd, Caerphilly.

They are all accused of Kerr’s murder through joint enterprise.

Kerr was pronounced dead at the scene and a stab wound measuring 13.5cm (5.3in) was later discovered during a post-mortem examination.

The court heard how he had bled heavily before collapsing in the arms of a friend and telling him: “I’m hurting. My side – I love you bro. You’re a good ‘un you are.”

Prosecutors said the exact motive of the attack was unclear, but text messages sent between Palfrey and Elliot showed they were dealing drugs, including cocaine, ketamine and cannabis, and discussing the collection of drug debts which they described as “straps.”

They, together with Mears were driven by Manny in her Volkswagen Polo around locations in Cardiff and Caerphilly.

The group arrived at the house which was home to a friend of Kerr in Abertridwr just after 17.30 BST, the court heard.

Kerr had gone to the house to play Fortnite and smoke cannabis with friends.

It’s alleged Mears went into the house armed with the knife, that witnesses said was about 10 inches long, slightly curved with holes in it, purple and silver in colour.

Mears said “alright boys,” a greeting which appeared to be directed at Kerr, the court heard.

Mears was described as “acting like a gangster”, repeating the phrase “What you want?” while brandishing the knife.

He was followed by Palfrey carrying a wooden stick, which one witness thought might have had a nail in it.

The court heard that around 40 minutes before the attack, Palfrey had turned his mobile phone off.

Palfrey warned the other people in the living room not to get involved. Elliot remained in the hallway acting as a look out.

Prosecutor Michael Jones KC said the fatal attack on the teenager took less than two minutes.

He said witness Connor Davies described Mears “stabbing and swinging out” at Kerr who tried to push him away, before seeing the blade of the large knife going into his coat.

Jones said Palfrey watched the attack while holding the wooden stick above his head “as if warning the others not to get involved”.

Others in the house believed he was in charge as he told them: “Stay away, let them have it out.”

The prosecutor added that it was as if Palfrey was the foreman stopping Kerr’s friends getting involved.

“Tristan Kerr died at the scene as a consequence of that attack and that fatal blow deliberately inflicted on him,” he said.

“Although that fatal blow was delivered by Georgie Mears, all four of them bear the joint responsibility for, and are therefore guilty of his murder.”

The jury was told Manny “undoubtedly” saw that two of her passengers were pre-armed and walked into the house immediately after Kerr was fatally stabbed and acted as the getaway driver.

After fleeing the scene in Manny’s car, the four were later arrested in Hereford.

The trial continues.