A teenager is facing life behind bars for stabbing a 15-year-old boy to death as he tried to steal his bicycle.
Joshua Williams, 18, lashed out with a blade as popular young student Alan Cartwright was riding along Caledonian Road, north London, with his friends in February.
At the time of the attack caught on graphic CCTV, Williams had been on police bail on suspicion of possessing a four-inch lock knife although he was never charged.
A jury took just three hours to find Williams guilty of Alan's murder and conspiracy to rob. He will be sentenced tomorrow at noon.
His co-defendants,18-year-old Shaquille Roberts and a 16-year-old have already pleaded guilty to the bicycle robbery and are also awaiting sentence.
Alan's family wept in court as the verdict was delivered before issuing a call for more stop and searches and tougher 10-year mandatory sentences for possessing knives to deter young people.
His father Alan Cartwright senior, 44, said: "It will make people think twice about carrying a knife."
The family are also hoping to organise an annual cycling event on Alan's birthday in aid of knife crime awareness charities, including the Ben Kinsella Trust.
Alan - who was known as Little Al by his family - was killed close to the spot where 16-year-old Ben Kinsella was also stabbed to death eight years ago, prompting a high profile anti-knife campaign led by his sister, the EastEnders actress Brooke Kinsella.
His death made headlines as "another tragic example of the knife crime that blights our society", prosecutor Jonathan Rees QC had told the court.
On the evening of February 27, Alan was cycling with five friends when Williams and two other youths intercepted them, the trial heard.
In just seven seconds, they stepped out in front of the cyclists and managed to take two bikes before the third robber approached Alan in the road and swung a knife at his chest in a "deliberate and gratuitous" stabbing, Mr Rees said.
Despite being mortally wounded, Alan did not come off his bike and he managed to cycle on before collapsing a short distance up the road outside the Cally swimming pool.
He was pronounced dead a short time later despite the efforts of a first aider, police and paramedics.
His heavily pregnant mother Michelle Watson, 40, rushed to the scene after hearing Alan had been stabbed, only to be told: "I'm sorry your son didn't make it."
On March 4, Williams went to Islington police station with his parents to hand himself in, the prosecution said.
When asked why they were there, his mother told an officer it was about the incident in Caledonian Road, saying: "Yes, he's involved, he did it."
And as he was taken into custody, Williams, who lived off Holloway Road, north London, was heard by another officer to say: "It's the right thing to do, isn't it?".
But in his defence, Williams claimed he was at a youth club that night and he only went to the police station to tell them that he was not involved in the incident.
The court heard that the defendant, nicknamed Slimzy, was identified as the third robber in a comment about the CCTV footage which was released by police and posted on YouTube.
His parents and brother also gave evidence to back up his claims - however the jury had spotted the apparently religious family did not all swear on the Bible in the witness box.
Mr Rees told jurors that his alibi was in tatters and the evidence from his family was "disappointing" because they had "decided to abandon their principles to support him in his lies to the court".
He suggested the defendant carried a knife on the day of the robbery because he was the victim of an earlier knife attack at the hands of a group of youths in Caledonian Road three months before.
The prosecutor pointed out that the CCTV showed the killer who wielded the knife was clearly left-handed - the same as Williams.
In a statement read to the court, Alan's mother Michelle Watson, 40, told how news of his death came as an "unbelievable shock".
She said: "Life without Al is killing me as his mum. It's also had a devastating effect on his family. He loved his dad Al senior. Al has not been able to go back to work since this happened.
"He says he cannot see a future without him. He was our loving boy - our only son."
Outside court, Detective Chief Inspector Chris Jones said: "I'm pleased with today's verdict. I'm pleased the jury rejected Williams' claims he was not responsible for his crime. I hope it reminds young people who may consider carrying a knife that they face some very real consequences."
Malcolm McHaffie, from the Crown Prosecution Service, added: "This was a completely unprovoked attack on a young teenager who was spending time having fun with his friends.
"This case shows the horrifying results of knife crime and how a life can be lost and a family devastated in a matter of seconds.
"CPS London is committed to tackling knife and gang crime in the capital and we will continue to work with our criminal justice partners to robustly prosecute offenders."