The B.C. SPCA said Sunday it has new evidence to forward to Crown counsel for possible animal cruelty charges against the Whistler, B.C. tour company that shot and killed more than 100 healthy sled dogs in April last year.

So far, animal welfare agents have dug up the remains of 52 of more than 100 animals buried in a mass grave near the popular ski resort city.

The agency believes exhuming the grave should be completed by Tuesday.

More than 50 of the bodies have been sent away for necropsies, but results will not be available for several weeks.

Marcie Moriarty of the SPCA said the agency is pursuing Criminal Code charges for causing unnecessary pain and suffering to an animal. If found guilty, the person responsible could face up to five years behind bars.

"Throats have been cut and the animal bled out. That is not an acceptable way to kill an animal in Canada," she said.

"If the animal was bludgeoned to death and didn't die instantly from a shot to the head for example. If multiple gunshot wounds and the science could show the first shot didn't kill the animal, all of those could be examples."

The SPCA estimates the investigation could cost up to $225,000. The provincial government has committed $100,000, while the rest will come from donations to the non-profit agency.

Moriarty says the hefty price tag is justified.

"This is absolutely worth it to speak for animals in B.C. We're an enforcement agency, we don't get to pick and choose what case we do," she told CTV News on Sunday.

SPCA members are being helped by a team of forensic experts from across North America, including some of whom who aided in the investigation of serial killer Robert Pickton.

The initial dig was severely slowed because of debris covering the ground, said forensic anthropologist Dr. Bill Hagland.

"We started out first couple of days as just moving hundreds of wooden boxes, dog house boxes. This is just a big dumping area for the work that these people do with the sled dogs tour group company."

Hagland said workers will begin working on their hands and knees with more delicate instruments once the remaining bodies are exposed.

"They're dead but they're going to have a story to tell us," he said. "I'm here to help the dogs."

Moriarty said the animals will get a proper burial after the investigation is complete.

News of the gruesome cull surfaced earlier this winter after workers' compensation documents were leaked to the media. The documents outlined a claim by a worker who said he was experiencing post-traumatic stress after killing the dogs.

The animals were under the control of a Howling Dog Tours. Another firm called Outdoor Adventures had a stake in the company when the cull took place, but insists it had no idea about what had happened.

In his claim, Robert Fawcell said he shot or slit the throats of at least 70 dogs in "execution-style killings" over the course of two days, at the end of a slow sledding season. In some cases, Fawcett stood on the animals with one foot to shoot them. Several that didn't die from the gunshots were stabbed multiple times.

Following a public outcry, the B.C. government appointed a task force to review the local dogsled industry. The task force published 10 recommendations last month, which include boosting penalties for animal cruelty, instituting standards for the sled-dog industry and increasing funding for B.C.'s SPCA by $100,000.

Premier Christy Clark endorsed the report's recommendations after it was released and pledged to enact what she called the toughest animal cruelty legislation in the country.

Clark said the province will increase the maximum penalty in animal cruelty cases to a $75,000 fine, 24 months in jail, or both. The current law allows for a maximum fine of $10,000 and a maximum jail sentence of six months. The changes will also extend the current six-month statute of limitations in such cases.