A post-mortem examination has confirmed father of two Michael Mulholland was seriously assaulted before his death in Taita, Lower Hutt, last Thursday.
The 52-year-old was found unconscious in a driveway near his Farmer Crescent home. Friends attempted CPR, which was continued by emergency services, but he died at the scene.
Operation Field inquiry head Detective Inspector Darrin Thomson said the post mortem confirmed Michael had suffered serious injuries before his death.
He said police were following several positive lines of inquiry in relation to the homicide investigation.
"Police believe a number of people visited Michael's home at 93 Farmer Crescent on Thursday 20 September 2012, and would like to speak with anyone who had contact with him at any time during that day as they may hold key pieces of information about what happened to Michael at about 10pm that evening."
Several houses on Farmers Crescent display signs of Mongrel Mob affiliation and police confirmed last week Mr Mulholland had Mongrel Mob connections.
Mr Thomson said Mrs Mulholland's family were still coming to terms with his death.
"Our thoughts are with Michael's family, and we are working hard to support them through this this tragic time. We are also very focussed on finding those responsible for his death and holding them to account."
A team of 25 Police staff were continuing to work on the investigation, he said.
Anyone with information can contact Lower Hutt Police on (04 560 2600) or call Crimestoppers anonymously on 0800 555 111.