A teenager who stabbed an Afghan refugee to death with a Rambo knife has been jailed for 10 years.
Hazrat Wali, 18, who came to the UK "in hopes of a safer life" died in hospital after he was fatally stabbed on playing fields in Twickenham in October 2021.
Hours earlier, the 17-year-old knifeman had walked free from court after being sentenced for carrying a knife at a shopping centre two months before.
He then went on to attack a McDonald's worker an hour after Mr Wali's attack.
The youth, who cannot be named for legal reasons, was found guilty of manslaughter at the Old Bailey on Friday after telling the court he had been carrying the weapon, but had not intended to seriously harm Mr Wali, an aspiring cricketer.
He was originally tried for murder and cleared by the jury, but convicted of the lesser charge.
Mr Wali suffered a 10cm deep wound after the knife was plunged into him at Craneford Way Playing Fields where a school rugby match was ongoing at the time.
Players described seeing injured Mr Wali picking up a branch before collapsing.
The court heard he had been "unarmed" and "outnumbered" by the defendant and his friends at the time.
The defendant, who was enrolled on a college course at the time, had been caught with a black knife at Southside shopping centre in Wandsworth two months before the killing, on August 5, 2021.
He pleaded guilty to that offence and was given a youth rehabilitation order at Wimbledon magistrates' court on the morning of the killing.
Jailing the youth, Judge Sarah Plaschkes KC told him: "When you stabbed Hazrat he was unarmed and outnumbered by you and your friends."
She said he made a "deliberate decision to carry a fearsome weapon" that day, adding: "You told the jury that you took the knife to the magistrates' court. You left it in some bushes outside and collected it once the hearing concluded."
Mr Wali's older brother, Mohamed Ashuk, told the court in a victim impact statement that his sibling came to London from Afghanistan "hoping for a safer life".
He added: "He was just settling into college and enjoying his new life in London and he wanted to study and become an engineer."
Mr Ashuk said his children were now afraid to leave the house for fear of being stabbed.
The court heard Mr Wali's twin brother arrived in the UK after the killing, and was "traumatised" by the news.
"He thought he would be reunited with his brother after travelling here from Afghanistan," Mr Ashuk said.
The elder sibling continued: "This was no accident but it was a deliberate and violent attack which has left me and my family in a state of devastation."
Mr Wali was sitting in the park with Mariam Ahmadazai, a female friend, on October 12 2021 when they were approached by the defendant and five other teenagers.
Prosecutor Jacob Hallam KC had said that one of the girls in the group made a comment that the pair "looked nice together".
The defendant, then aged 16, began swearing at Mr Wali, who got to his feet and approached him.
Mr Wali was pushed by the defendant, then rang a male friend for help saying he was going to be in a fight.
The defendant then produced a 20cm long black knife with zigzag-shaped indentations on the blade and, following further exchanges, stabbed Mr Wali in the right side, causing a 10cm deep wound and massive blood loss.
Fatally injured, Mr Wali grabbed the defendant's jacket and asked: "Why did you stab me?"
He picked up a fallen branch but collapsed soon afterwards.
A teacher from a local school gave first aid and emergency services attended but they were unable to save his life and Mr Wali died about an hour later.
Giving evidence in court, the youth said he grew "scared" when Mr Wali called his male friend for "back-up", and added: "I thought he had something on him, a knife."
At the time of the killing, the youth said he sometimes "felt unsafe" walking on the streets and would carry a knife for "protection" after incidents in which he, a cousin and a friend were attacked.
Under cross-examination, the youth admitted attacking another inmate while on remand at Feltham Young Offender Institution a month after the killing.
In a phone call, he had bragged that he and another inmate had targeted the victim in the showers.
He said: "Me and (the other youth) got into a scrap with some yout' from Luton. We f* him up, he's still in hospital."
On Boxing Day 2021, he came up behind a fellow inmate and punched him to the back of the head, and then took part in the melee that followed.
He pleaded guilty to affray and was sentenced to a four-month detention and training order, the court was told.
Garry Green, defending, said his client suffered trauma from witnessing domestic violence when he was younger and has been subject to social services since he was two years old.
He was convicted of manslaughter as well as admitting affray and assault occasioning actual bodily harm in relation to the second attack on the McDonald's worker, and was sentenced to 10 years and eight months' detention at the Old Bailey on Friday.
In early 2015 when Mr Wali was just 13 years old, he left Afghanistan for his own safety and to start a new life.
He lived for a short time in Austria before moving permanently to the UK and settled in London in 2017.
Scotland Yard said he was described by all those who knew him across all care settings as shy, friendly, polite and respectful to everyone he met.
