Specialist investigators from the East Midlands Unit have taken over a murder case in Northampton.
Daniel Fitzjohn was stabbed in Kingsley on Thursday evening.
Two arrests have been made so far with a 23-year-old woman and a 27-year-old woman arrested on suspicion of assisting an offender.
They have both been released under investigation pending further enquiries.
Police are appealing for anyone who saw two men in the area around the time of the incident to get in touch.
One is a male in his 20s with close-cropped hair, the other is a black or Asian male who was wearing a dark hoodie.
Detectives would also like to speak to anybody who saw a grey Mini driving erratically in the surrounding area.
Anyone with information is urged to call 101 or if you would prefer to remain anonymous, call Crimestoppers on 0800 555111.