Louis-Ryan Menezes, 17, died on Friday evening (May 25) following an incident in Drayton Walk in the St David’s area of Kingsthorpe, Northampton.
Up to 50 officers are now working around the clock on the investigation, which is being led by the East Midlands Special Operations Unit (EMSOU) major crime team.
Det Supt Neil Castle, who is leading the inquiry, said: “We have had a lot of co-operation from members of the community who have been talking to us and providing us with many lines of inquiry to investigate.
“Officers have been conducting house-to-house inquiries in the area over the weekend and we are making positive progress.”
Northamptonshire Police have stepped up uniformed patrols in the area and anyone with information is being asked to speak to officers on the ground.
Det Supt Castle said they were particularly keen to speak to anyone who was in the Drayton Walk area of St David’s between 6pm and 7pm on Friday or was in or around Eastern Avenue North or the shopping parade in Newnham Road.
He said: “It’s possible you may have seen people acting suspiciously in the area at the time or perhaps you have private CCTV or dashcam footage which might provide crucial information to help us find out what happened.”
A Home Office post mortem examination carried out over the weekend indicated that Louis died from a stab wound to the chest.
Three people arrested on Saturday in connection with the incident have been released without charge.
Anyone with information is asked to call police on 101 or Crimestoppers, in confidence, on 0800 555111.