The photo shows a 34-year-old man who died in hospital after being attacked in a park.
Ryan Burton, from Corby, died at University Hospital Coventry on January 16, six days after the attack at Spring Rise park in Kettering.
A murder investigation is underway and six men have been arrested in connection with the incident which happened shortly before 7pm on Friday, January 10.
Four of the men are from Kettering and are aged 38, 24, 24 and 22.
A 20-year-old man from Desborough and a 24-year-old man from Rothwell were also arrested and remain in police custody.
Ryan Burton (pictured) died at University Hospital Coventry on January 16, six days after the attack in Kettering's Spring Rise park.
Formal identification procedures have yet to be completed, but detectives believe Mr Burton is the victim.
Specialist officers from the East Midlands Special Operations Unit (EMSOU) Major Crime team are supporting his family.
Witnesses or anyone with information, including CCTV, doorbell or dashcam footage of the area at the time, who has yet to come forward, can call Northamptonshire Police on 101, quoting incident number 25000018864.
Alternatively, information can be submitted via an online portal: Public Portal (https://mipp.police.uk/) or by calling Crimestoppers in confidence on 0800 555111.
