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– After his dog Bleu sustained a leg injury over the summer, Andres Figueroa brought the 7-month-old dachshund to a sleek clinic outside of Portland.

But in the exam room, the veterinarian said, Bleu tried to nip at him. He snatched the dog by the mouth and torso with such force that Bleu defecated on the table, Figueroa said, and then lifted him into the air by the snout until he began to lose consciousness.

Distraught, Figueroa recovered his dog and left. By the next day, the dog's lungs were filled with fluid and he had to be put down. "I knew I had to call the police," Figueroa said.

After going to the authorities, Figueroa discovered that the veterinarian, Dr. Daniel Koller, had decades of complaints filed against him in two states by regulators, customers and employees.

Across the country, there is less accountability for veterinarians than there is for practitioners who treat people. While courts award multimillion-dollar judgments for negligence in hospitals, states treat companion animals as a form of property, and owners have little opportunity to sue for damages beyond the cost of a replacement. There is no data repository to track problematic veterinarians, and state review boards rarely put sanctioned practitioners out of business.

Practicing in both California and Oregon off and on for the past 30 years, Koller first faced a criminal charge of animal cruelty three years after he got his license in 1974; regulators in California said he was seen kicking and beating a German shepherd that employees later found dead. He had his license revoked for that and other abuse allegations in 1979 and restored in 1984.

His license was suspended again in 2001, when his daughter called 911 to their home, where paramedics found Koller's wife unconscious and him semiconscious with a puncture wound in his arm, regulatory records said. He later admitted to using Telazol, a veterinary anesthetic.

'I am not a danger'

In the 1980s, Koller built a network of budget veterinary clinics in Oregon, where officials suspended his license in 2008 and revoked it in 2010. He returned to practice five years later.

In interviews with the New York Times, eight customers detailed concerning encounters at Koller's clinics in the four years since his license was most recently restored.

One said Koller snatched her dog by the scruff of the neck with such force that the dog wet the table. Another said the doctor choked her frightened puppy. Some had concerns after their pets that went in for surgery ended up dying.

Koller declined an interview request. But in a 2015 memo to Oregon officials, he said he maintained high standards for care and cited support from numerous veterinarians. "I am not a danger to my patients," Koller wrote.

Disciplinary actions are rare

While there is no nationwide database for the public to track veterinary discipline, state records show the rarity of serious enforcement actions. In Oregon in recent years, about 6% of complaints handled by the veterinary board resulted in the finding of a violation.

In states that make enforcement reports readily available, including Arizona, Nevada, New Jersey, New York and Pennsylvania, records show cases in which veterinary personnel who had racked up five board actions or more were able to continue practicing.

Lori Makinen, the executive director of the Oregon Veterinary Medical Examining Board, said enforcement in human medicine and veterinary medicine cannot be compared because society does not place as much value on an animal's life.

But Linda Rosenthal, a member of the New York state Assembly, said states should acknowledge the changing relationships that people have with their pets. She said she had been exploring a plan to establish pets as a special category under tort law, somewhere between people and property, but expected strong resistance.

Much of the case against Koller prepared by California regulators in the 1970s concerned his treatment of the German shepherd at a pet hospital outside Monterey.

An administrative law judge wrote that a woman had brought in the stray animal for treatment of a leg injury. The judge found that on two occasions in July 1975, Koller hung the dog off the ground, beating it with his hand and foot until it lost consciousness. The dog lost three teeth.

Employees later found the dog in the freezer used to store dead animals, according to the veterinary board documents.

A jury convicted Koller of animal cruelty, and he was sentenced to 100 days in jail.

The veterinary board in California was looking at a range of other concerns.

In October 1974, regulators said, Koller pounded the head of a Lhasa apso named Tammy "until both eyes were hemorrhaged," documents said.

In 1975, officials found evidence that he beat a dog named Coco for several minutes when the dog would not stop barking; bit and pounded a dog being prepared for surgery; used a slip lead to suspend a dachshund by the neck for at least 30 seconds; and slammed a cat on the sides and floor of its cage.

In 1979, the board revoked his license. Five years later, it reinstated it.

'I'm a litigator'

Koller, who had apparently been studying the law when he was barred from veterinary practice, began aggressively defending himself in court.

After a customer complained in 1987 that Koller had hurt her cat's leg by handling it roughly, Koller filed a defamation lawsuit against the customer and several others who had criticized him. Court records indicate that the case was settled.

"I'm a litigator," Koller once said, according to a 2004 article in the Oregonian. "I like the courtroom battle."

In the years that followed, customers continued to come forward with complaints about rough handling of their pets and unexpected deaths during surgery.