A "wholly innocent" 16-year-old boy was "in the wrong place at the wrong time" when he was shot dead on a canal towpath, a jury has heard.
Lewis Dunne was on his way to a shop when he walked into the path of four men lying in wait with a loaded weapon and with "murderous intent", Liverpool Crown Court was told.
The shooting in Vauxhall, Liverpool, was said to be the culmination of a series of incidents in the area on November 15 last year between two groups of males which involved the deliberate ramming of vehicles, chases and violence on the streets of the city.
Opening the prosecution case, Ian Unsworth QC said: "Put shortly, at the time of the fatal attack upon Lewis Dunne the defendants were intent on revenge.
"They had obtained a deadly loaded firearm and acting as a group they sought revenge upon those they opposed and who they had had trouble with earlier that day.
"Lewis Dunne was not involved in any of those previous incidents. He was simply on his way to the shop at the time that he lost his life.
"Whether he looked like one of the opposing group or whether they simply believed he was one of the opposing group, they used the gun to shoot him dead as he unwittingly walked into their path."
The prosecutor added: "Lewis Dunne had no axe to grind with these men. He had done nothing wrong."
Three of the men who took part in the "cowardly attack" alongside the Leeds and Liverpool Canal were in the dock, Mr Unsworth said, but police had not yet been able to identify who they say the fourth man was.
Jake Culshaw, 25, of no fixed address, and brothers Paul Martin, 25, and John Martin, 20, both of Ince Avenue, Anfield, deny murder.
The prosecutor told jurors at Liverpol Crown Court: "There is no direct evidence to to say which of those four men pulled the trigger and shot Lewis Dunne.
The simple fact is this - he was shot in the back by one of a group of four males who had walked in darkness along that canal towpath armed with a loaded lethal weapon.
"That we cannot say which person actually shot him does not matter.
"In short, we suggest on a proper analysis of the evidence … each of the three defendants bears the responsibility for the death of Lewis Dunne."
Jurors heard that Lewis - described as "a quiet lad who kept himself to himself" - lived at home with his family, not far from where he was killed.
He contacted a friend at 10.24pm on Sunday November 15 to ask if he could borrow a bicycle to ride into the city centre about a mile away and buy some cigarettes.
Lewis arranged to meet up on the canal towpath to collect the bicycle and told his mother he would be home in about 20 minutes as he set off on his fateful journey.
At 10.36pm the teenager walked under the Eldonian Bridge on the towpath and moments later CCTV footage captured swans reacting suddenly and some dark figures running along the canal side after he had been shot.
A ballistics expert was later to observe that Lewis may have been shot from a distance of between four and seven metres away, Mr Unsworth said.
The prosecutor told the jury: "This was a truly cowardly attack.
"Why was it that four males were lurking under a canal bridge in the dead of night, armed with a loaded shotgun possessed of, say the prosecution, murderous intent?
"The answer to that question is we suggest one that is well known to each of these three men.
"Earlier that day there had been a series of incidents which tended to suggest that there was animosity between their group and another group of males.
"You will hear of vehicles being involved in deliberate rammings, chases and violence on the streets in the locality."
Among those incidents, spanning up to four hours, was the ramming of a stolen Mini Cooper, said to be linked to John Martin and Culshaw, by a black Peugeot vehicle.
The Mini was later abandoned and the Crown say two of its occupants ran into the Green Man pub and hid in the ladies toilets from those in the Peugeot.
Nearby, a group of men - said to be associated with the Peugeot - burst into the Castle pub and one of them was later described as having curly hair sticking out of his baseball cap.
Culshaw was eventually tracked down by his pursuers and was attacked in nearby Green Street, Mr Unsworth said.
The prosecutor told the jury that those associated with the Mini Cooper had come worse off.
He said: "They had lost their vehicle, they had been chased and one of their number had been assaulted. Whatever this was all about it seems clear that they were not intent on letting things go. They wanted revenge."
It was later that Lewis - who had noticeably curly hair - was "simply in the wrong place at the wrong time".