Imported Pets a Growing Business in U.S.

"I feel awful about what he went through," Mullins said. "You don't know how much you love something till it's gone and that's how I felt when Otis passed away."

The Internet is full of sites that claim to be selling lovingly raised local puppies, but actually deal in imports from Eastern Europe, Russia, Asia and Central America.

Mattie Rodriguez bought Lola online. She says her puppy was sick the moment she brought her home. She says she later found out Lola was a Russian import.

"She has a million problems, and my vet says, 'You got a lemon,' but you know what, I really love my lemon," Rodriguez said.

But she now warns other dog lovers about buying puppies online.

"Be very, very careful and do a lot of homework," Rodriguez said. "Don't be in a rush, don't fall in love with the puppy because they're really cute and all cuddly. If you want to get a good, healthy full-bred puppy, you should wait and really do your homework on that breeder."

Dog Auctions

More than the dog's health is at risk, in some cases. The Centers for Disease Control and Prevention say some importers are selling puppies before they're old enough for a rabies vaccination. In March, a dog from India flew through Seattle on its way to Alaska before it was diagnosed with rabies.

"So if you're bringing in unvaccinated puppies, there's a chance that a puppy is going to come through that is incubating rabies, which is lethal for people," said Nina Marano, an animal importation expert with the CDC.

The CDC is currently proposing stricter regulations for dog imports.

"We want the puppies to have been vaccinated before they come to the United States," Marano said.

Older, female breeding dogs can be imported as well, and may end up at animal auctions.

Exclusive video from the Humane Society of the United States' undercover investigation shows auctions where breeding dogs are bought and sold.

The auctions are perfectly legal, but the Humane Society went undercover to document the conditions of some of the dogs face — cramped cages, cold temperatures, no food or water for hours on end.