A six stone XL Bully mauled its owner before escaping from police to go on an hour-long rampage through a quiet Norfolk village, forcing a primary school to be evacuated.
The animal, from the recently banned breed, was eventually killed by officers in the school grounds after a member of the public was able to secure it to a post.
The dramatic events unfolded in Brisley, near Dereham, close to the time when pupils were being picked up on Monday afternoon.
The animal - named Denvor - first attacked its owner while she was exercising it in the back garden of her home on Gateley Road.
She was overpowered, pushed to the ground and mauled, suffering serious injuries.
Her cries for help were heard by people on nearby allotments who alerted police.
Armed officers arrived at the scene and attempted to get the dog off its victim, with the use of Tasers and a fire extinguisher.
They were eventually able to free the woman, who is in her 60s, but the animal came off its lead and escaped through the garden gate.
The animal - which was adopted by the owner from the Dogs Trust less than a month ago - then roamed through nearby fields before heading towards Brisley Church of England Primary School, in School Road, which has 75 pupils aged five to 11.
It was shortly after pick-up time and staff and children still at the school were evacuated to a nearby field as a large police presence cordoned off a section of the road.
The dog was found in the school car park where a member of the public managed to secure it to a post.
Attempts were made to find a vet to sedate the pet, but none were available so, with the permission of the owner, officers euthanised it at the scene.
The victim remains at the Norfolk and Norwich University Hospital where she is having reconstructive surgery. Her injuries are not life-threatening.
Her husband, who rushed home from work after receiving a desperate call from her during the attack, said she was “lucky to get away with her life”.
“We don’t know what set him off,” the victim’s husband, who requested not to be named, said.
“He showed no signs of aggression whatsoever. He just didn’t seem like that sort of dog.
“He loved my wife to bits and would sit on the sofa with her resting his head in her lap.
“We just don’t understand why he did it and we never will. Something must have triggered him.”
The government announced a ban on the American XL Bully breed last month after a series of high-profile attacks around the county, some of them fatal.
The breed will be added to a list of dogs banned under the Dangerous Dogs Act by the end of 2023.
Government officials have said there will not be a cull of the breed but owners will have to register their pets, make sure they are neutered and insured, and muzzled in public.
Denvor's owner said he did not blame the breed for Monday's attack.
“I’m angry about what he’s done, but I’m not angry at the breed,” he said.
“I had spoken to other owners and read up about the breed and I had no concerns whatsoever.
“I spoke to another owner who has four children and he said his dog was good as gold.
“I’m trying to defend him the best I can but it’s hard to do so when you look at the injuries.
“I can’t condone what he has done. He had to be put down and I understand that.”
Belinda Allen, headteacher of the school, said: “Our school staff were alerted by the police that there was a dangerous dog and immediately actioned staff to clear the area.
“There was no immediate danger to staff or children within the school area.”
The Dogs Trust, in Snetterton, had rehomed Denvor within recent weeks.
A spokeswoman said he had "no history of aggression" and seemed to have "settled well into his new home".
She added: "Our priority at this time is to provide as much support as possible to people affected by this incident, and we will be undertaking a thorough investigation."
Insp Diana Woodage, from Norfolk police, said: “This was a terribly sad and distressing situation.
“Officers were faced with an incredibly difficult situation when they arrived at the scene – a woman being viciously attacked by her dog and was very clearly injured and in some pain.
“In the interests of public safety and at the request of the owner, the dog was humanely destroyed.”
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