Staff and volunteers at the Vancouver SPCA are worried sick after a dog that was seized during an animal cruelty investigation was stolen from their care.

Employees say the dog, a six-month-old pit bull terrier named Isis, was taken by a man who visited the shelter on Tuesday afternoon and expressed interest in adopting her.

After he signed paperwork and provided photo ID, he was allowed to take the dog out for a short test walk. He never returned.

"I believe he was asked to steal the dog, and sold it to the person who asked him to steal it," said Kim Monteith, the SPCA's regional animal welfare supervisor.

Shelter staff called police immediately. They tracked the man, who is known to police, to his address in Coquitlam, but the dog wasn't there.

Monteith said Isis was originally rescued from "horrible living conditions," where she was kept with multiple dogs and neglected.

"I don't know if she's back with the abusive owners, I don't know where she is," Monteith said. "Our concern, with the staff and volunteers, is her well-being no matter where she is."

Worried employees have posted ads on Craigslist and contacted veterinary clinics, shelters and rescue groups in Metro Vancouver to get the word out.

"Anybody who'll listen we're asking to keep their eyes open for her," Monteith said. "If somebody happens to find her and they want to drop her off at a local shelter anonymously, I'm sure the shelters will take her and then notify us."

Isis weighs about 45 lbs., is mostly black with white marks on her paws and chest and has uncropped ears. She was wearing a red and black Silverfoot Martingale collar with a native design on it when she was stolen.

Anyone who thinks they have seen Isis is asked to contact the SPCA at 604-879-7343.