Four people have been convicted of murdering an NHS worker they selected at random to kill in the street in an attack meant to boost their standing in a gang. David Gomoh, 24, was attacked in Newham, east London, as he spoke on the phone to his girlfriend who heard the opening words of the attack, as one gang member asked: “Where are you from?” The court heard that the four convicted on Wednesday at the Old Bailey had gone looking for a rival gang member to hunt down and murder on 26 April 2020, at the height of the first coronavirus lockdown. Instead they killed Gomoh, a university graduate, whose father had died days earlier from Covid. He was stabbed 10 times moments from his doorstep, and managed to stagger home where he collapsed at his front door. The Guardian has learned that one of the gang members, Vagnei Colubali, had been deported from the UK in 2017 but smuggled himself back into the country, according to multiple sources with close knowledge of the case. The brutality of the murder and the fact gang violence, usually targeting other rivals, was visited on someone wholly innocent, made the case unusual. Those convicted were affiliated to the Northside gang, who declared themselves “at war” with gangs from the south of the impoverished borough in east London. Those convicted and their ages at the time of the attack were Mohammad Jalloh, 18, David Ture, 18, Colubali, 22, and a youth aged 16. The attack was planned, with the killers making sure their mobile phones were off to avoid later detection by police. The car had false number plates, a sock was used to stop fingerprints being left on the steering wheel, and the four carried a change of clothes. The gang rode around in a stolen car and, with two of them wearing sunglasses and masks, they went after a black man selected at random, who ran as their car slowed down and escaped. They “eyed up” a second man, but he was left alone, police believe, because he looked older than the usual age of a gang member. Later they spotted Gomoh. He had left his home to go to a local shop at 10.23pm. The gang exited the car, said “where are you from?” to Gomoh, who was on the phone to his girlfriend, and he ran. The gang chased him and inflicted 10 knife wounds. The attack lasted seconds, with Gomoh, who worked in NHS procurement, sustaining stab wounds so ferocious they severed arteries, damaged internal organs and cut through bone. Some wounds were more than 10cm deep and five could have been fatal. The attackers had differing backgrounds. Jalloh had done well at schooland was a drug dealer who claimed to be making £1,000 a week and used a £35 a night hotel room to stash his drugs. The youth who cannot be named for legal reasons, lived in Telford. Colubali was caught on CCTV wearing an Armani bag and bragged to a friend he had killed someone in his native Portugal. David Ture had in 2018 been convicted for stabbing someone in a fight and at the time was in a hostel. There he is believed hours after the murder to have drawn a “comic strip” depicting parts of the attack, which homicide detectives later recovered from his bedroom and which helped seal the convictions. DCI Larry Smith, who led the murder investigation, told the Guardian the “comic strip” confession by Ture was unheard of in his nearly two decades as a homicide detective. In the drawings, Ture depicted the clothes the attackers wore and a man on the ground. Smith said: “I’ve been investigating murders a long time. It is rare that someone is wholly innocent and unknown to their attackers.” The detective said Gomoh’s sister and mother, Marian, who works at Newham general hospital, were heartbroken, and contrasted the decency of the hard-working family he came from to his killers. Shortly after the stabbing Ture and Colubali were spotted on CCTV, high-fiving. Smith said: “They did not care that they had just butchered someone.” He added: “If David walked outside his house a minute later he would have still been alive and the car with these horrible people in would have driven past.” Marian Gomoh said the loss of her son was “painful beyond words” and added: “David’s murder is without doubt the hardest thing my family and I have been through. It is something that no parent should ever go through.” The prosecutor, Oliver Glasgow QC, told the jury: “North Newham is at war with south Newham; it is a violent war; it is a war that involves knives and guns; it is a war that sees one side head into enemy territory in the hope of attacking the opposition; it is a war that has seen both sides suffer casualties; and it is a war that the members of the opposing gangs appear to revel in.” All four will be sentenced on 17 September for the murder, which carries a mandatory life sentence, and for conspiracy to commit grievous bodily harm. Before the attack, Jalloh and the youth who cannot be named appeared in videos bragging about attacking rival gang members.