A veterinary clinic in Texas allegedly convinced a family to euthanize their 5-year-old Leonberger for health reasons, only to secretly keep the dog alive in a feces-covered cage for six months for blood transfusions.

Last year, Marian Harris took her family's dog, Sid, to the Camp Bowie Animal Clinic in Fort Worth to be treated for a gland issue. As the condition worsened and Sid developed problems walking, the vet reportedly recommended they put the dog to sleep. Marian agreed and told police she gave Dr. Lou Tierce permission to euthanize Sid.

Six months later, the Harris family received a call from Mary Brewer, a former technician at Camp Bowie, who claimed Sid was still alive and being held in a urine-and-feces-covered cage for blood transfusions.

"I told her, 'He's still here,' and she's like, 'Can he walk?' and I said, 'Yeah, he's here waiting on you. If you came today, he'd walk out and jump in your car,'" Brewer told NBC DFW.

Marian and her husband, Jamie, rushed to the clinic, where they found Sid, alive and in a cage.

"It was like getting punched in the stomach and then some," Marian Harris said. "This has rocked our world. My kids are like, 'How does somebody do this?' How does this happen?"

The Harrises freed Sid and immediately took him to another clinic, where vets said he didn't need to be euthanized at all. According to the Harrises' attorney, vets said Sid had been "abusively kenneled" and likely used for blood transfusions.

"He was able to walk and jump in the back of my minivan so it was an excitement to be reunited," Marian told CBS DFW. "The betrayal is so incredibly intense that nothing you have prepares you for the emotions. There's anger, there's joy that you have your dog back, there's betrayal of this intense trust. And so it's just really hard to camp on one particular emotion."

Authorities went to the clinic Tuesday and seized several animals. The Texas State Board of Veterinary Medical Examiners has called an emergency meeting in Austin; a member of the board is set to meet with Ft. Worth Police and prosecutors on Wednesday to discuss criminal charges.

UPDATE: Tierce was arrested later Wednesday on animal cruelty charges. On Thursday, his license was suspended.

[h/t Daily Mail]