A couple's discovery of their missing dog for sale on a pet adoption Web site led police to a Long Island home where more than 50 dogs were living in squalid conditions, authorities said.

The dogs, some sickly and underfed, were taken Wednesday night from the Melford home by staff members of a Suffolk County animal protection agency to a shelter to be examined by veterinarians, authorities said.

"The house was in horrible condition," said Roy Gross, chief of the Suffolk County Society for the Prevention of Cruelty to Animals. "It was covered in feces and urine. It was hot, very hot in there."

Karen Schleich, 45, and David Bernacchi, 44, who said they lived in the house, were arrested and charged with animal cruelty, police said. Schleich was also charged with criminal possession of stolen property — a Shih Tzu that a Long Island couple said went missing on Saturday.

Police were trying to determine whether any of the other animals also had been stolen.

Police said Wednesday night that they did not know if the couple, described as boyfriend and girlfriend, had attorneys. They also arrested Kristin Beauchesne, 25, of Shirley, on a charge of grand larceny.

Sgt. Michael Cosgrove, of the Suffolk County police's crime section, said that Beauchesne had an attorney, but he could not immediately provide a name.

The three claimed that they were animal rescuers, and they posted advertisements for dogs on various pet adoption Web sites, Cosgrove said.

Bernacchi ran a dog rescue organization called Lucky Fund, Newsday reported in Wednesday's editions. The mission of the company is "to help and place as many dogs as possible with new and loving families," states a message on the Lucky Fund Web site.

One couple searching for their Shih Tzu found their newly shaven dog advertised for sale on one of those sites — for $350, he said. They contacted police, and an investigation led to the Medford home, Cosgrove said.

Beauchasne was arrested after a witness reported seeing her take the Shih Tzu from the street on Saturday. She told a police officer who stopped to question her that the dog had escaped from her backyard, police said.

Friends and neighbors of Schliech and Bernacchi said the couple was only trying to protect the animals. Louise Castro, the owner of a nearby coin-operated laundry, told Newsday on its Web site that Schliech "lived for those dogs."

"She loved them," Castro said. "She would never do anything to hurt them."

But Gross, the SPCA chief, said the conditions in the house were "deplorable" and that it appeared that the couple was not properly caring for the dogs.

"Basically, they failed to provide proper sustenance," he said.

The three suspects were in custody and scheduled to appear in court Thursday. All of the dogs taken are available for adoption, authorities said.

It was not immediately clear whether the Shih Tzu was reunited with its owners.