Detectives have arrested a teenager on suspicion of the murder of 14-year-old Jaden Moodie.
The suspect, 18, was arrested in Wembley, north west London, on Saturday morning, Scotland Yard said.
Jaden was stabbed to death on Tuesday January 8 after he was rammed off a moped by five men in a black Mercedes B class, police believe.
Three of the attackers got out and knifed Jaden before all of them fled in the car.
The suspect has been taken to a police station in central London where he is still being questioned, the Metropolitan Police said.
Detective Chief Inspector Chris Soole, from the force’s homicide and major crime command, who leads the investigation, said: “Although one man has been arrested in connection with this murder, we remain fully focused on locating and arresting others connected to this deadly attack.
“Our efforts to bring them to justice continues. A number of active enquires are in hand.
“I would urge anyone with any information about this crime to contact us without delay.
“I understand that some people may have reservations about contacting the police, but please be assured that any information provided will be treated in the strictest confidence.
“My team are ready to take your calls.”
The Mercedes used in the murder, which happened at about 6.30pm in Bickley Road, Leyton, east London, was recovered the following day.
Det Ch Insp Soole said police still want to speak to anybody who might have seen the car in the area before Jaden was killed.
He added: “Jaden’s family are being fully supported and kept updated by our team.
“This is a truly heartbreaking time for them and we are doing everything we can to find out who was responsible for Jaden’s death.
“Due to the location and time of the attack we know there are a number of people out there who either witnessed the incident or who have information about this heinous crime and we would like to hear from them.
“I firmly believe that someone out there knows the people who are responsible for Jaden’s murder.”