Nehemie Tampwo, Brian Sasa, Tyrique King and Zenay Pennant-Phillips, all aged 19, deny the murder of Keelan Wilson, who was stabbed more than 30 times in Wolverhampton on May 29, 2018.
Keelan was allegedly killed amid growing tensions between Wolverhampton’s V2 and V3 postcode gangs.
Barristers began their closing speeches on Tuesday at Wolverhampton Crown Court.
Mr Michael Duck, prosecuting, said: “That young man was killed in Strathfield Walk by a gang of young men who decided he was going to die. That is the brutal reality of this case.
“Wound after wound inflicted on Keelan Wilson as he lay utterly helpless on the ground.
More from the trial:
“This was the planned killing of a young man who hadn’t reached his 16th birthday.
“Keelan Wilson had swapped from the V3 to V2 group. Swapping his allegiance was enough for people to think his life had to come to an end.
“On May 29 there had been two incidents as a result of tensions between V2 and V3.”
The defence barristers are yet to begin their speeches.
Mr Chambers QC told the jurors as part of his split summing up: “It’s not disputed that at about 11pm a 15-year-old boy was murdered.
“He was repeatedly stabbed with long-bladed weapons, probably machetes, which inflicted some 32 wounds.
“The central issue in the case is whether the prosecution has made you sure that each of these defendants participated in the attack.
“Prosecution says this is a gang-related killing by the members of V3 gang, seeking violent retribution against Keelan Wilson as he had dared to change sides from V3 to V2, their arch rivals.
“The prosecution says it is no coincidence that day a leading member of the gang was released from prison.
“During that day there were various attempts to seek retribution.
“They gathered in a house then together went in a taxi to an area of Wolverhampton where they expected Keelan Wilson to be and they jointly assaulted him.
“The defence case is each defendant denies he is a member of any gang. They each deny they participated in any attack.”
Mr Chambers said that defendants Zenay Pennant-Phillips, Nehemie Tampwo and Tyrique King said they were not present and were using the alibi defence.
While Brian Sasa said he could not remember precisely where he was but he was likely at an associate’s address.
Sasa, of Long Ley, Heath Town; Tampwo, from Fern Grove, Bletchley; King, of Chelwood Gardens, Bilston, and Pennant-Phillips, whose address cannot be published for legal reasons, have all denied murdering Keelan.