The dogs thought to have killed three cats and a dog in vicious attacks in Rotorua have yet to be caught.
Some Hillcrest residents and pet owners feared a child might be next after three cats, one dog and a guinea pig were killed by dog attacks last month.
Animal Control team lead Dylan Wright said a dog had been impounded as part of the investigation into the attacks in the area.
"An identification process was carried out with two attack witnesses, however neither were able to positively identify the dog," Wright said.
Wright said officers also carried out a search at the dog owner's property as witnesses of the attacks had reported seeing two dogs.
However, there was no evidence in the search to suggest a second dog was at the property and the dog has since been released.
"Animal Control officers will monitor the situation and continue the increased patrols and priority responses in the Hillcrest area," Wright said"
Peter Bangs had previously told the Rotorua Daily Post he feared for his grandchildren's safety after their family cat of 20 years, Karma, was killed in their garden less than a month ago.
"Some people can't have children and they get a cat or a dog ... they're family."
Bangs said his elderly neighbour's cat had been killed after Karma, and said he had heard of four cats mauled in the same area since.
"Something needs to be done, it's not just one cat, it's five family pets," Bangs had said.
Animal Control urges residents to contact the council immediately if a roaming dog is seen.
As the evidence threshold to prosecute a dog owner is high, the Animal Control unit did not have enough information in this particular case to continue to hold the dog or move to prosecute the owner.
• Team of seven officers, minimum of four on patrol daily and minimum of two on weekends.
• After-hours officers are on call after 4.30pm and respond as needed to jobs phoned through.
• Attacks are a priority one job: they are responded to immediately, 24 hours a day.
• When reporting a dog a photograph (if safe to do so) and/or a detailed description of the breed and, if known, the address from which the dog emerged or is known to live.