Marian Harris said the family's 5-year-old Leonberger, Sid, was to be put down last fall because of a degenerative spinal condition.
Instead, the family claims, the pet was kept alive to be "bled" for plasma and other experimental treatments.
Fort Worth police and officers from the Texas Board of Veterinary Medical Examiners on Tuesday raided the Camp Bowie Animal Clinic in west Fort Worth.
The clinic has been operated for many years by Dr. Lou Tierce.
Jim Eggleston, the family’s lawyer, says allegations have surfaced that more dogs and cats — some with serious illnesses — were being kept alive for blood transfusions and other experimental treatments.
“You have a vet keeping dogs under false pretenses,” he said. “You have family pets that people thought were cremated or put down peacefully that may still be alive.”
A person who answered the phone at the clinic Tuesday morning said Dr. Tierce was too busy to talk.