Nancy Waddell rescued Riva from a Taunton racetrack in 2003 when the greyhound was 2 years old through a Salisbury organization called Greyhound Adoption Service.

Nancy, a home health aide, and husband James Waddell, a locksmith and lobsterman, socialized the skittish dog, which they said had cattle prod scars on her belly from her days at the track, and nursed her to a more healthy weight in their Prospect Street home in Rockport.

But on May 5, 2006, Riva died from heat stroke in the office of veterinarian Dr. Jeffrey French.

Nancy Waddell had taken Riva to the Barking Lot on Main Street in Gloucester to be washed and groomed at 8:30 a.m. When she returned to pick her dog up at 12:30 p.m., she said she found Riva lying on the wooden floor shaking, panting, unable to get up.

Now the question of liability rests at the center of a lawsuit the Waddells filed in Gloucester District Court this month. Nancy Waddell said Rosey Lourenco, owner of the Barking Lot, put Riva into a drying box, which is an enclosed heating unit groomers put animals in to dry their fur, after a wash.

"Riva basically roasted from the inside out because (Lourenco) forgot about her," Waddell said.

Lourenco referred all questions to her attorney, Patricia Johnstone.

Johnstone said Animal Control Officer Jamie Levie and Martha Parkhurst, an agent with the Massachusetts Society for the Prevention of Cruelty to Animals, both investigated Riva's death and found no wrongdoing.

Levie and Parkhurst did not return phone messages seeking comment.

"It's a tragedy any time a pet dies," Johnstone said. "I'm sure the Waddells are suffering from the loss of their pet. But Martha Parkhurst found no grounds for legal action. Jamie Levie found no grounds."

The Waddells said they are pursuing a civil suit, filed April 5, because intent to be cruel is necessary for criminal action. They said they know there was no intent to be cruel or to kill the dog.

Johnstone said the Waddells have not listed damages in the suit and any loss of business for Lourenco would be included in a planned countersuit.

"As far as my client is concerned, this is a baseless and frivolous lawsuit," Johnstone said.

Nancy Waddell took Riva to French's office and a line in Riva's medical record from French's office dated May 5, 2006, stated that Riva had been at a groomer's and collapsed. The dog was "unable to walk, panting" and had a temperature of 108.7 degrees.

The report states Riva had heat stroke and the veterinarian started cold towel soaks and administered oxygen and intravenous medicine.

Waddell said Riva was in good health. She took the dog to Tufts University Grafton Small Animal Hospital for a necropsy, which is an autopsy performed on an animal.

Nancy Waddell said she could cope with the loss of her dog, but Lourenco denied any responsibility in the death.

"I basically felt they were trying to get me out of there because they knew the dog was basically dead," Nancy Waddell said. "If she had just took responsibility and apologized, we wouldn't be doing this."

"What we hope to accomplish is for her to be accountable for what happened," James Waddell said, adding any award they may receive beyond court and attorney costs, and the $700 bill for the necropsy, will go to Greyhound Adoption Service and to Best Friends, an animal sanctuary in Kanab, Utah.

The Waddells went back to Greyhound Adoption Services about two weeks after Riva's death and adopted Maggie, who had raced in Hollywood, Fla.