Five teenagers aged 16 and 17 have been arrested over a fatal stabbing.
Stefan Valentine Balaban, 19, died after being stabbed in the chest in Whitchurch Lane, Edgware, on July 28.
Police and ambulance crews were called at approximately 1.05am but Stefan died at the scene.
Four boys aged 16 and a youth aged 17 were arrested on suspicion of murder after raids in north London this morning (August 1).
Stefan's family have been informed and are being supported by specialist officers.
A post-mortem examination held on Saturday (July 29) gave the cause of his death as a stab wound to the chest.
Detectives from the Met's Specialist Crime Command are leading the investigation and enquiries are ongoing.
Det Chief Insp Neil John said: "My thoughts are with Stefan's family as they come to terms with this awful news. We will do everything we can to support them and bring whoever is responsible to justice.
"These arrests mark significant progress in a fast-moving investigation. We believe there are outstanding suspects and our work to trace those people continues.
"Our work is far from finished and we need the public's help. I remain keen to hear from anyone who has information, no matter how small or insignificant it might seem.
"I would also like to hear from any drivers who was passing through the area and have dash cam footage to come forward."
Anyone with information should call 020 8358 0100.
Alternatively, call 101 quoting CAD 334/28Jul.
People ca also contact Crimestoppers anonymously on 0800 555 111.
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