"Police are also continuing to investigate whether there were others who assisted the primary offender on the night."
Last month a 47-year-old appeared in the Wellington District Court as the sixth person to be charged in relation to the homicide of Tongia.
Three other women have been charged with his murder in varying degrees, and another man and woman have charged with being an accessory after that fact.
Police asked anyone with information to contact them on 105 and quote file number 201220/8063.