The Far North District Council is still looking for the pack of six dogs that attacked 95-year-old Jim Morgan's dog Sandy in Harold Ave, Kaikohe, on December 16.
There was initial hope Sandy could be saved by the amputation of his left hind leg, but he was euthanased two days later.
The council's environmental services manager, Darren Edwards, said on Tuesday that the animal management team had investigated tips from the public, but neither the dogs, nor their owner (who was riding a blue quad bike that residents had seen before, and believed to be local), had been identified.
Staff would continue to canvass residents in the hope someone could provide the information needed.
Mr Edwards urged anyone who knew where the dogs had come from, or who owned them, to call the council on 0800 920-029.
"In the meantime we have stepped up animal management patrols around the area of the attack, and in Kaikohe generally."