DNA tests pinned a savage mauling that left a girl with 17 horrific wounds on a pet Staffordshire bull terrier.
Johanna McQuillan had chunks of flesh dangling from her legs.
The nine-year-old needed two hours of surgery after the attack as she played in a park with her three-year-old sister.
Distraught Emma Hastings had her pet Staffie Mally seized by police this week when swabs revealed he was responsible for the attack. He was returned to the 24-year-old yesterday – and she had him put down right away.
In tears, mum-of-one Emma said: “They told me that they had carried out door to door enquiries with my neighbours and were satisfied that he could be brought home.
“But I knew I still had to put him to sleep. I had to pick him up and take him to the vets.”
Emma did not know Mally had escaped from her home in Ayr before the attack in April.
She took the dog to police after recognising a description. Officers took swabs and collected other evidence.
The case is thought to be one of the first times DNA testing has been used in a dangerous dog investigation in Scotland.
Johanna’s dad John last night paid tribute to Emma. He said: “It was very noble of her to come forward.
“I’m really sorry for her. I think it was a mistake the dog got out.
Distraught owner Emma Hastings agreed to have her dog, right, put down
“We see the scars on Johanna every day. She is psychologically scarred as well as physically.
“But I just wish the dog didn’t have to be put down and I’m sure Johanna feels the same.
“The owner is a good citizen. It is a family pet and I really am sorry for her. We don’t bear her any grudges.”
Mally was allowed to remain at home with Emma and her young child until this week.
Weeping, Emma said: “I never ever imagined Mally would have been capable of something like this.
“This has made me doubt whether you can really trust your animals.
“It shows any dog can change. A little girl has been left permanently disfigured and will probably be afraid of dogs for the rest of her life.
“I want to say I’m so sorry to the family. My dog was not brought up to be vicious and I’m absolutely devastated.”
Emma backed our Stop The Danger Dogs campaign to target irresponsible owners who do not control their pets properly.
She said: “I believe that all dogs should be muzzled when they are out.”
A Police Scotland spokeswoman said: “A 24-year-old woman will be subject of a report to the procurator fiscal in connection with this alleged incident.”