A teenager who died after being stabbed has been named as Louis-Ryan Menezes.
Northamptonshire Police said they were making "good progress" in the investigation in to the death of the 17-year-old in Northampton.
Three people arrested on Saturday were released without charge. The force did not say what they were suspected of.
Det Supt Neil Castle said the community had helped police develop lines of inquiry in to the motive for the attack on Drayton Walk in Kingsthorpe.
Mr Menezes was pronounced dead at Northampton Hospital.
A post-mortem examination found he died from a stab wound to the chest.
Mr Castle, 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.
Police have appealed for anyone who was in the Eastern Avenue North or Newnham Road areas of Drayton Walk between 18:00 and 19:00 on Friday to contact them.