Police are not ruling out further arrests into the homicide of Rau Tongia, after a sixth person was charged last month in relation to his death.
Rau Tongia, 33, was found in his Karori home on December 20.
Detective Sergeant Steve Wescott said police were continuing to make "good progress".
"Inquiries continue to be made in relation to the firearm recovered throughout the investigation," he said.
"In particular, police are interested in understanding who had the firearm in the days and weeks prior to the shooting."