Roxie, an 18-year-old pit bull-shepherd mix, got out of the backyard of her family's home last Tuesday.
Corinne Stalter said it happened fast, in about 15 minutes.
The family searched the neighborhood and posted photos on websites and social media. A neighbor eventually found Roxie and took her to Maricopa County Animal Care and Control.
"When our staff saw her, she had a very large tumor around her neck," MCACC spokeswoman Melissa Gable said. "Our staff felt like she was in distress and having difficulty breathing."
Cellphone video shows Roxie in the lobby of the shelter before she was handed over. It's the last moments of Roxie's life.
"At that point, the vet made the decision that she was suffering and we could ease that suffering, so he determined she should be humanely euthanized," Gable said
Roxie was euthanized within an hour of being dropped off at MCACC. Her family received notification that MCACC had her just moments after she was put down.
"'What do you mean you killed my dog?' I was screaming and shaking," Stalter said.
She didn't think MCACC would do that so quickly.
"It wasn't 72 hours; it wasn't anything," Stalter said.
"There is an exception if the animal is suffering," Gable said. "The agency has the right to make that call, and decided is it inhumane to keep the animal alive and can euthanize right away."
Roxie's owner doesn't believe what MCACC told her and she wants answers.
"I want the vet's name," Stalter said. "I want to know who did this to our dog. Why did this happen?"
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