Lake Oswego, Ore. - Ken Griggs likes his new dog, but he preferred the old one. Then again, it might be the same dog. In a possible case of mistaken identity, Griggs said the black Labrador named Callie that he left at a Dundee kennel before spring break was not the same dog he picked up a week later.

"It's a sweet dog," Griggs said of the impostor living at his Lake Oswego house. "It's tough because now we've had the dog for 10-plus days, and the kids, especially the younger ones, start to get attached to the dog. I like it, but I want mine."

Allison Best, owner of the Tail Wag-Inn boarding kennel, said Griggs has the right dog. But Callie's vet examined the dog Griggs brought home and found evidence that it's not Callie.

"We know it's not Callie," veterinarian Andrea Frost told The Oregonian newspaper.

Griggs said he immediately noticed differences in the dog he picked up from the kennel. The family cat - normally friends with Callie - hissed at the dog. Callie would heel; this dog did not.

Griggs returned the dog to the kennel and Best examined whether Callie might have gotten mixed-up with any of the other black Labradors staying there that week.

Owners of the seven other black Labs all said they had the right dog.

However, the owner of Dixie, a dog Callie shared a kennel with, said her dog had undergone a "personality change," Best said. But after three or four conversations that day, the owner maintained she had the right dog.

Still, Best arranged for the owners and their dogs to meet March 31 for a possible exchange. The woman called saying she was late, Best said.

Meanwhile, Griggs had arrived with his family. A black Lab got excited when the Griggses approached, the kids declared it was Callie, and into the car the dog went.

It was the same dog the Griggs had just returned.

"It's uncanny how much it looks like my dog," Griggs said. "I'm sure it was happy to see us and recognized us from the day before and mistook us."

But still unsure, Griggs took the dog to his vet.

Callie had once surgery to her left elbow; this dog showed no trauma. Callie also had steel sutures after being spayed; this dog had none that showed up on the X-ray. The dog also seemed to have had a rapid weight loss.

Griggs has hired a lawyer, but Best says the case is closed.

"Mr. Griggs kind of lost his credibility with me the second time he came into the kennel with his family and reclaimed the same dog," she said. "If he can't recognize his dog, I don't feel I can be any help."