ORANGE PARK, Fla. -

Clay County detectives have arrested Candice Mullis and Justin Stone on charges they provided fraudulent registration and shot records for at least seven dogs for a total of $1,900.

Some of the dogs became ill shortly after being purchased through ads on Craigslist. The Sheriff's Office says some dogs died and others required expensive life-saving medical treatment.

One Ponte Vedra couple paid $6,000 in veterinary bills on a dog named Bella (pictured, below) they bought from Mullis and Stone. In the end, the dog still had to be put down.

Hopes were high as Nyrya Bresnihan and her family bought Bella days before Christmas.

"I've never used Craigslist, so I didn't think anything of it. I just thought it was fine," Bresnihan said. "Everything seemed fine. I didn't think there was anything out of the ordinary until I got home that night."

Bresnihan said the pit bull puppy didn't look like the one in the ad and was sick.

"She wouldn't eat anything, she wouldn't drink anything," Bresnihan said. "So I brought her to the vet the next day and they said she just didn't seem right."

For ten days, veterinarians tried to help the dog, but it was too sick, and $6,000 later, her owners said they had to put Bella to sleep.

"It was miserable," Bresnihan said.

She said the suspects sold her the dog for $250, complete with shot records, a checkup history and purebred paperwork. But she noticed things weren't right. The vet on the papers was nowhere to be found, and they appeared to be fake. That's when she alerted deputies.

"We actually went to the state of Florida and proved with the Department of Business and Professional Regulation that that vet did not exist," Detective Will Roberts said.

Roberts worked the case and said Mullis and Stone made fake papers and sold the dogs to several different people as part of a scam. Roberts said he found out they had done the same thing they did to the Bresnihan family seven different times. And each of those dogs was so sick it either died or had to be put to sleep.

"They were going through great lengths of hiding their identity," Roberts said. "They were being secretive. They were using aliases."

It is unclear where exactly the sick puppies were raised or if a "puppy mill" type operation was involved.

Anyone else who purchased a dog from the couple is encouraged to contact the Sheriff's Office.

Stone, 23, and Mullis, 24, of Middleburg, were arrested Monday and charged with organized schemes to defraud.

Neither responded to phone calls Tuesday seeking comment.

The Bresnihan family is still upset about what they went through -- the result of a scam they say was downright mean.

"I have nothing nice to say to them," Bresnihan said.