Two animal lovers who were willing to help the dog shot dead by police have questioned claims it was aggressive.
It comes as a video has emerged showing the dog laid calm in Mainsforth Terrace before Cleveland Police decided it should be destroyed.
Scores of people attended a vigil close to where the dog, believed to have been a Caucasian shepherd dog, was destroyed on Sunday afternoon after being left tied to a pole.
Dozens of dog lovers and owners attended the vigil and laid candles, flowers and lights.
A petition has now been backed by more than 126,000, with over 45,000 from the UK, calling for justice for the animal.
Town dad and daughter Graham Davies, 51, and Jenna Davies, 29, say they were both on the scene from 10am and saw people even hand-feeding the dog.
Graham said: “As soon as we saw a photo of the dog online we went down to the scene.
“There were another couple of people there and they were actually hand feeding the dog.
“The dog was even responding to commands and was sitting to get the food.
“It did bark a bit, but it was certainly not vicious or aggressive, it was eating out of people’s hands.”
Jenna said the dog had been there all night, it was cold and distressed and obviously frightened.
But she said: “The more it was eating the more calmer it was becoming because it was starving, as it was getting a bit fuller it was calming down. We just sat beside it and it was happy with the company.”
They said the chain was wound really tightly around the pole, so the group couldn’t get near enough to get it undone.
Jenna added: “We didn’t think for one minute it would be shot because it wasn’t aggressive.”
The dad and daughter said when the police arrived it became clear to them that the dog was frightened of the high visibility jackets.
Jenna said: “We said it was the jackets, but they just told us to move. I said it wasn’t us who were upsetting the dog.”
The pair claimed the police were on the scene for a few hours before an RSPCA officer arrived.
Jenna said: “Things moved really quickly once the RSPCA officer arrived on the scene and then they started talking about shooting the dog.
“We tried everything that we possibly could to save the dog, we were begging and pleading, but they just weren’t listening.
“If the dog had been rescued, assessed and then needed to be put to sleep in a calm manor that would have been a different thing, but to shoot it like that was just barbaric.”
Cleveland Police declined the opportunity to comment further after explaining earlier about their handling of the incident.
“Throughout the operation police worked together with a number of veterinary professionals, the RSPCA and a re-homing charity. This led to the decision to destroy the dog, which was extremely aggressive and unapproachable,” it said.
Assistant Chief Constable Jason Harwin said earlier: “We are always saddened by the death of an animal, but the difficult decision to destroy the dog was taken in partnership with animal welfare experts,” he said.
“The decision was made at the end of a six-hour operation, after we had exhausted all other options, including attempting to trace the owner and re-homing.
“Veterinary professionals told us that, even if the dog could have been successfully sedated, they couldn’t have rehomed the dog due to its aggressive behaviour and that this was the kindest course of action.
“If the dog couldn’t be rehomed, then the likely outcome would have been that it would have been euthanised by a vet.
“We also took on board advice from specially-trained officers at the scene and engaged with vets to try to attempt to resolve the issue long-term. However, sadly the only safe decision was to destroy the dog.”
Police said the dog was microchipped but it had not been registered and are still appealing for the owner to come forward.