Relatives said Mr Wali, 18, a student at Richmond Upon Thames College, who was attacked during a fight in Craneford Way, Twickenham, had come to the UK two years ago for a better life.
A relative living in Stanmore told the Standard: “Hazrat was a very good boy. He came here to study, he was living all on his own in London. His immediate family are all back in Afghanistan.
“I saw him in hospital. He had a fight is all that I’ve heard.”
His close friend Sahil Kochay said: “He was a very good person. Very caring and loved everyone.
“He didn’t hold any hate towards anybody. He used to stand up for everyone. I wish I knew why someone would hurt him. He wasn’t the kind of guy to fight.”
He was stabbed to death on a sports field in front of schoolchildren whose teacher ran over to give CPR in a desperate attempt to try to save his life.
The 18-year-old was attacked during a fight on a footbridge before staggering and collapsing onto the playing fields in Craneford Way, Twickenham, at 4.45pm on Tuesday.
The teacher shielded year 8 pupils, aged 12 and 13, who had been playing rugby, before tending to the victim. The pupils were said to be in tears as they witnessed the horror.
The 18-year-old is the 25th teenage killing victim of 2021 in London, with the city on track for its worst ever year for such deaths.
Police and paramedics attended the scene yards from neighbouring Richmond upon Thames College and close to The Stoop — the home of Harlequins rugby team.
Detectives have called on people who filmed the attack not to share it on social media.
One woman said her 13-year-old son saw the victim drop to the ground.
“The victim and suspects were arguing for a while. The teacher realised what was going on and moved the younger kids away from them,” she said.
“The older ones kept on walking to the footbridge where the row carried on. The teacher went over, the boys scarpered and the poor boy dropped to the ground. He was the first to realise he had been stabbed.
“The teacher did an amazing job.
My son is now petrified of knives but he is level-headed and okay. He said it was quite far away but he did see the boy collapse.”
A witness said: “There was a teacher in a rugby kit, he was trying to save the boy. He was giving CPR. There were two girls next to him, they were crying. He was a real hero, it was a terrible scene.
“Five minutes before the incident a group of very noisy kids came along were heading to the field. The next thing we knew all hell let loose.”
Another resident said the teacher “was fighting so hard to save the lad”.
The victim was taken to hospital where he was pronounced dead an hour later. Scotland Yard said his family are being supported by specialist officers.
The pitch is now a crime scene, with two police tents, and cordons are in place. There have been no arrests.
The murder happened in Richmond, one of London’s safest boroughs.
Richmond upon Thames College on Wednesday confirmed the victim was a student there and the college was supporting other students who had been affected and had increased security.
Dr Jason Jones, the college principal, said: “Our thoughts and prayers are with the student’s family and friends at this difficult time. This loss is sure to raise many emotions, concerns, and questions for our students, parents, staff and local community.
“We have implemented our College’s Emergency Response Plan. This will provide assistance to our students as necessary and has evolved from Local Authorities’ experience with death in the past and the advice of mental health professionals from the community. We have deployed additional resources to the Student Services team who are providing support and counselling to students and staff on site.
“Safety remains our number one priority and we will continue to do all we can to keep our students safe at college. To that end, we have enhanced security and surveillance at our entrances following yesterday’s incident and are continuing to work in full co-operation with the Metropolitan police, who are handling the matter”.
Richmond Upon Thames School said their headteacher was writing to parents today expressing “how shocked we are to hear of the senseless death”.
It said in a statement: “While the teenager didn’t attend Richmond Upon Thames School a loss of any young life is a tragedy that affects all of us.
“Knife crime is a London wide problem, and the headteacher would like to emphasise how important it is for parents to talk to their children about the dangers of carrying any type of weapon.”
The Met has launched 107 homicide investigations in 2021, of which 25 involved teenage victims.
If the current rate continues, the number of fatalities for the year will top 30 youngsters for the first time, overtaking the peak of 29 in 2008, as well as the 26 recorded in 2019.
Detective Chief Inspector Vicky Tunstall, who is leading the murder investigation, said: “The incident occurred in a playing field area and was witnessed by a number of people.
“Some of those people are believed to have filmed events as they unfolded. I ask that any videos are not shared via social media to avoid causing the young man’s family any more distress. Instead, please go to the police immediately.”