Three young men who killed a teenager in Thornton Heath in a “terrifying, violent attack” over a gang rivalry fuelled by taunting online music videos have been found guilty of murder.

Jermaine Goupall was 15-years-old, standing outside a Costcutter in Green Lane, when a group of people wearing balaclavas and armed with knives and machetes pulled up and chased him down.

Most of the group of people Jermaine was with took cover in the shop, but the teenager was chased on foot with the car following, until he was caught and stabbed.

Police were called to the scene around 11pm that night, August 8, 2017, as bystanders rushed to the teenager’s aid.

Despite the public and emergency services best efforts, Jermaine had had his femoral vein in his leg severed and he bled to death.

Prosecutor Mukul Chawla said the attack was linked to the CR0 gang and the attack was intended to be targeted towards a rival gang called CR7.

He said: "They were nothing more than a marauding gang of thugs who had gone to Thornton Heath and were there to hunt down anyone whom they thought was from the CR7 gang unfortunate enough to get in their way.

The prosecutor said tensions were raised between the two gangs following a series of music videos posted online in which they "taunted" each other.

He said: "The motivation for the attack appears to lie in the fact that each of the defendants is part, or connected with members, of the CR0 gang.

"The evidence demonstrates that this was a pre-planned attack with knives or similar implements on those that they thought were part of the rival CR7 gang."

The Met Police said they believed Jermaine himself was not an active gang member.

The three found guilty of murder today (February 14) were:

• Adam Benzahi, 21, from Carshalton

• Samuel Oliver-Rowland, 18, from Epsom Road in Croydon

• Junior Simpson, 17, of Northdown Crescent, Croydon

Saskia Haye-Elliot, 18, of Northdowns Crescent in Croydon, was found guilty of manslaughter.

DCI Tony Lynes, who led the investigation, said: "Jermaine and his group of friends were targeted by armed suspects with their faces covered who chased Jermaine and carried out a terrifying, violent attack.

"I can only imagine the fear Jermaine felt as he was attacked. Members of the public rushed to his aid as they tried to stem the bleeding and keep Jermaine calm before the emergency services arrived and continued to administer first aid, but tragically he died from his injuries.

"These four defendants denied involvement, but the weight of evidence against them was enough to convince a jury of their guilt.

"Jermaine's senseless murder appears to have stemmed from gang rivalry and violence, and we now have a family left utterly devastated and the lives of all involved blighted forever.

"I would like to highlight the courage and dignity Jermaine's family have shown since his death and throughout the trial, and I hope the verdict and upcoming sentences will offer them some comfort and help ease their enduring grief as they continue to come to terms with their tragic loss."

The guilty defendants were remanded in custody to be sentenced at the Old Bailey tomorrow.