Detective Chief Inspector Mark Wrigley, who leads the investigation, said: “We have arrested five people and continue to make good progress, but it is clear that there were more people who witnessed Sven’s murder.
“If you were in Willesden Lane at around 5.40pm on Saturday, 6 February and saw anything, however insignificant you think it might be, I’d like you to get in touch and tell us what you saw.
“Were you in the area at the time? Did you see or hear anything? Do you have any mobile phone or dash camera footage? Any detail, no matter how small, could help us.
“Sven’s family has been left utterly devastated and we are doing everything we can to bring those responsible to justice.”
Anybody with information is urged to call police on 101 or tweet @MetCC quoting CAD 5580/06Feb.