The brutal murder of a teenager was sparked by sickening taunts over the death of a Marlow schoolboy in the River Thames, a court heard today.

Three High Wycombe teenagers on trial over the killing of Wa'ays Dhaye last year have blamed the attack on the cousin of 13-year-old Kyrece Francis who died while swimming with friends in 2014.

The trio stand accused of ambushing Slough teenager and stabbing him to death yards from his home, after he made his way back from Notting Hill carnival last year.

They all deny murder and have pointed the finger of blame at a fourth man, Kyrece’s cousin Davarn Francis - who fled the country before the court case.

Summing up the trial at Reading Crown Court, defence lawyers told jurors Francis' motive for knifing Mr Dhaye was over sickening taunts he had received relating to the death of his young cousin.

On the day of the murder, Khianni Gordon, 18, and another youth who cannot be named for legal reasons, had been driven to Slough by 19-year-old pal Kaneel Huggins, along with Francis.

Prosecutors claim the murder was then committed, but lawyers representing the three youngsters on trial have told jurors that it was Francis who inflicted the fatal wounds on 18-year-old, Mr Dhaye.

He was repeatedly knifed on a doorstep before staggering down Thurston Road, in Slough, - the road where he lived - and collapsing in a pool of blood.

The teenager, known to friends as Bigs, was on his way home from the Notting Hill carnival on August 31 last year when he was attacked.

Robert Marshall-Andrews, defending Gordon, today said: "He [Davarn Francis] has disappeared.

“The main man has decamped, using a passport from his father. He hasn't been back in time for this trial; his absence the most articulate indication of guilt.

"The Crown say they don't know who struck those blows, but we do. They were struck with one knife over a period of seconds. We know who struck them; it was Francis.”

Mr Marshall-Andrews continued to point to Francis having the main motive, despite claims from the prosecution that Gordon has been involved because he was left incensed at other derogatory comments made on social media about a YouTube video.

Speaking about the comments over Kyrece, he said: "It's a deeply unpleasant taunt about a boy who was dead. That's what drove him."

Prosecutors claim the three defendants were all involved, adding that they had scoped out the area three days before the attack, when they hid in a cul-de-sac and ambushed the Somalian national as he walked home from the railway station with his headphones in following an argument at the carnival.

However Robert Marshall-Andrews, defending Gordon, today told jurors that the blame for the killing lay with "the absent Francis."

Mr Marshall-Andrews said that in the moments before the stabbing, Francis's eyes had been described by witnesses as "popping and bulging" and he appeared "totally psyched", as if ready to launch an attack.

He added that the initial confrontation was between Francis and Mr Dhaye, and the two who joined in later were Gordon and the unnamed co-defendant.

Mr Dhaye suffered a deep 10cm cut to the abdomen and numerous other blows to his legs and buttocks.

Huggins, drove the other three men to the scene in his Vauxhall Corsa.

Gordon denies a separate charge of perverting the course of justice, after the Corsa was set alight in woodland in nearby Marlow, in an attempt to destroy evidence.

Huggins has admitted the charge, and although Gordon said he was present at the scene he insists he did not torch the vehicle.

Wa'ays Dhaye was stabbed to death just yards from his home in Thurston Road, Slough.

The court heard that the three youths had got into a fight with Mr Dhaye and his friends at the Notting Hill Carnival earlier that day over a "running grievance", with prosecutors saying this lead to the attack.

John Price QC, prosecuting, said: "Police learnt of a dispute or argument of some sort carried out on social media involving Mr Gordon and Wa'ays Dhaye, and that this had spilled over into an argument involving the two men whilst both of them had been at the Notting Hill carnival.

"The two groups had to be kept apart from each other by some police officers, but it wasn't serious - you might take the view that the whole thing was despairingly immature.

"There's this argument brewing between them. They come across each other at the carnival and that was the catalyst for the events of that night."

Gordon and Huggins, both of Cullyn Road, High Wycombe, and the third defendant all deny murder. Gordon denies perverting the course of justice.

Trial judge Johanna Cutts QC is due to start her summing up of the four weeks of evidence tomorrow (Wednesday).