Two witnesses to a vicious dog attack in a Richmond park say screams brought them running towards the victims, a young child and two twin sisters who call themselves “Twins that toke THC” on Instagram and whose overdoses and drug use has raised concerns about the dog’s care.

Elliott Jackson picked up a log to ward off the dog until RCMP officers arrived, while his girlfriend Brooklyn Purdy called 9-1-1 and sat with one twin who was bitten over 100 times until an ambulance came.

“What the dog did, it was terrifying to watch,” recalled Purdy. “Nerve-wracking. It was the worst experience of my life.”

Twenty-one-year-old twin sisters Kati and Jessi Mather were both injured in the attack, and hailed as heroes for trying to protect Jessi’s three-year-old son Jayden from the jaws of Yogi, a Rottweiller-Husky cross raised by Kati and her boyfriend Luke.

The boy was unhurt, though his father said he is having nightmares. Jessi Mather was injured, but Kati Mather was worst affected, with at least 100 bites, a broken arm, and a detached bicep. She recovered from surgery after the shocking attack. The dog is now in custody.

“This one was very extreme,” said animal behaviorist Dr. Rebecca Ledger. “A hundred bites in a single victim – it’s among the worst attacks I’ve heard of.”

Friends have said the dog was always well-behaved. But Ledger said it’s likely there was something that sparked the attack.

“Generally it’s rare for dogs to attack out of the blue. Usually there is a history of anxiety and fear,” she told CTV News.

Many factors can cause anxiety in dogs, from a medical issue to repeated mistreatment, she said. She said she has seen cases where dogs react badly to someone impaired on alcohol or drugs.

“Substance abuse can be an issue,” she said.

An Instagram account called “Twins that toke THC” shows the Mather sisters drinking, smoking marijuana, and partying. It uses hashtags including #bongbeauties, #stonerbabes and #sisterswhosmoke. THC is the active ingredient in marijuana.

One post, from 32 weeks ago, says, “Gettin high was a daily routine since 13.” But in a later post made in September on Facebook, Kati Mather says that she “ended up in hospital more than 3 times in the past year from ODing and being ridiculously close to death too many damn times.”

It’s not clear which drug resulted in the overdoses. She says in the same post that she is getting clean.

One person moving out of Kati Mather’s Richmond home told CTV news on Saturday the drug use was continuing. He did not want to go on camera, but said the twins would get high on “downers” and yell at the dog and threaten it.

A person who answered the door at the home denied that there was any abuse. “The animal was spoiled, that’s all I’m going to say,” the man said, before slamming the door. He re-opened the door and said the dog was given treats and trained before shutting the door again.

Purdy, one of the Good Samaritans, said she worried about drug use creating an “unstable, toxic environment” for the dog.

“If you’re in an environment where there’s drug use you’re not able to take care of the animal as you should,” she said.

Recalling the incident, Purdy said she was nervous as her boyfriend Elliott Jackson approached Yogi.

“I didn’t know if he was going to hit the dog, and then he’d come at Elliott,” she said. “It would be one more person getting hurt.”

Jackson said he saw another man, Ken Brodie, try to kick the dog, but he got bitten. Jackson approached with a log as Yogi mauled Kati Mather, and he was getting ready to strike.

“The dog has her. She’s yelling at me to hit the dog. But I froze. I started talking to him. He looked at me for about five minutes until the cops came,” he said.

When police arrived, the dog attacked again, Purdy said.

“The cops scared him away – three shots,” she said, adding she saw the ground explode. The dog wasn’t hit, and ran off. It was apprehended nearby.

According to Richmond legislation, any dog that has injured a person is classified as a dangerous dog. Animal control officers can propose to euthanize the dog, and can do it quickly if the owner agrees. If the owner disagrees then Animal Control must seek an order from the Provincial Court.

Sometimes dangerous dogs can be rehabilitated with training, said Dr. Rebecca Ledger. But this attack was so terrifying it’s unlikely this dog will survive, she said.

“This is such an aggressive attack it wouldn’t be safe to rehabilitate the dog at this point,” she said.