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.
- nzherald.co.nz