A 25-year-old man was seriously assaulted before he died from his injuries in Whangārei on Saturday night, police say.
At the time, police only said he was seriously injured in an incident involving a group in Raumanga.
On Monday, police said they had established he was seriously assaulted and that the people allegedly involved in the assault had also been struck with a vehicle.
"There are a number of aspects we are not in a position to comment on publicly in our investigation, however, we do not believe this incident is gang-related," Detective Inspector Dene Begbie said.
"We are following positive lines of enquiry and are committed to holding those responsible to account."
The dead man's family were "understandably devastated", Begbie said.
Police continued to urge anyone with footage of the incident to pass it on to them, but pleaded with people not to post it on social media because it might affect their investigation.
"We ask you do not share this footage online and instead upload it to the dedicated portal."
Police also asked anyone who was in the area of the Gull service station about 9.30pm on 15 April, and who had not yet spoken to them, to contact them on 105 or online at using at Update My Report.
Information can also be provided anonymously via Crime Stoppers on 0800 555 111.