Four teenage boys were in custody today after a 15-year-old boy was stabbed to death in a planned attack by suspected rival gang members as he arrived at school.
Zac Olumegbon, from Brixton Hill, south London, and a friend were ambushed by four young men at the gates of Park Campus School in nearby West Norwood.
The car used by the gang suspected of the murder was found on Saturday in Holland Grove, Stockwell, south London.
Detectives are appealing for anyone who saw the green Nissan Almera in the last few days to get in touch.
Det Ch Insp John McFarlane said it was stolen on June 29 in Brixton.
He said: "I am appealing for anyone with information on the whereabouts of this car since it was stolen and who may have been using it to come forward.
"It is believed to have been driven in the Lambeth area in the days since its theft."
A post-mortem examination found the cause of death was stab wounds to the chest.
Two of the boys in custody were arrested on Friday, one on Saturday and another yesterday.
Police believe four black males arrived in the car before the attack and a confrontation took place outside the school on Friday morning involving the two victims.
The pair were then chased into Gipsy Road Gardens, where Zac was repeatedly stabbed.
His 14-year-old companion ran back to the school to seek safety but was attacked in the grounds and stabbed in the arm.
Police, London Ambulance Service and an air ambulance attended the scene at 8.50am, where they found Zac suffering multiple stab wounds.
He was taken to a south London hospital and confirmed dead shortly after arrival.
His companion was also taken to a south London hospital, suffering minor injuries.
Tributes to the dead teenager were left at the scene and on microblogging site Twitter and social networking site Facebook.
More than 3,000 people joined a Facebook group called R.I.P Lil Zac.
Zac was the 13th teenager to be killed in the capital this year as senior officers pull out all the stops to keep a lid on violence among young people.
Hailed as the first of its kind on its launch two years ago, Park Campus is a specialist school educating some of London's most troubled young people.
Three other teenagers, all arrested on Friday, were bailed.Reuse content