"Inquiries about the weapon's whereabouts are continuing and we are making some good progress in our area canvass as well as speaking to witnesses and taking statements," Mr Harrison said.
"We have also had about half a dozen calls from the public after our appeal for information about movements at the property, and the information provided has been helpful with our ongoing inquires."
"I want to thank those who have rung in with information and strongly encourage anyone else who saw any people or vehicles frequent the Ormond St property on the Sunday to contact police."
A 20-strong team of officers are working on the investigation and the scene examination at the property is ongoing but is expected to be completed within the next 48 hours.
"We are also continuing to communicate with the Whatuira family as the investigation progresses and support them as they grieve," Mr Harrison said.
For investigative reasons he said police will not be commenting any further on the nature of the injury at this stage.
Anyone with information is asked to contact Detective Constable Claire Adkins on (06) 210 2201.
Information can also be provided anonymously to the organisation Crimestoppers on 0800 555 111.
