Warning: This story discusses graphic details of animal cruelty.
The SPCA is looking for information about the death of a dog left hanging from a tree near Whakatāne.
On 21 August, the animal welfare charity were made aware of a white, young adult, bull-breed female dog at the Onepu Mountain Bike Park.
After speaking to the forensic pathologist, inspector Liisa Jones said the dog was alive when she was hanged and would have died slowly, as dogs have a secondary blood supply to the brain.
"Studies have shown dogs can take between 12 and 20 minutes to pass away from a hanging which is prolonging their distress.
"It appears in this case, from the report, this dog could have taken up to 30 minutes to pass away from the way she was suspended from the tree."
The dog also had extensive bruising to her internal lower abdomen, Jones said.
Two members of the mountain bike community found the dog, she said.
The park is well used and has registered about 24,000 users a year, including dog walkers, runners and mountain bikers.
"It is quite disturbing because it appears someone has had to think about the way they've done this and the tools they have needed to do the job.
"To do it in such a public place, it is frequented daily by many people, so I'm not sure what the person's thought process was around that."
However, Jones said this ill-treatment was not something she had seen often.
The dog was not registered and the SPCA is now appealing to the public for witnesses or information.
"Our lines of enquiry have dried up at this stage ... any information coming forward we will further investigate. Sometimes insignificant information can help move an investigation forward."
Jones said she was horrified and the dog would have been incredibly frightened and in pain.
"Even if we can't get enough evidence to do anything, at least we can get some education out there that it is an offence against the animal welfare act that it is an offence to ill-treat an animal and this isn't an acceptable form of euthanasia.
"They could talk to a vet clinic, or the SPCA as opposed to taking such a drastic action against an animal."
SPCA urges anyone with information to contact Rotorua SPCA on (07) 349 2955, quoting job number SB366725.