The man who admitted to killing more than 100 sled dogs in Whistler in 2010 has been criminally charged in the mass slaughter.

The Criminal Justice Branch of British Columbia announced Friday that Robert Fawcett, a dog-sled operator at a Whistler-based company, faces one count of causing unnecessary pain or suffering to a number of dogs after dozens were culled when tourism slowed following the Winter Olympics.

“We are extremely pleased,” said Marcie Moriarty, the general manager of cruelty investigations at the B.C. SPCA, whose probe led to the charge. “This was definitely the largest animal investigation that we’ve ever conducted.”

The probe had to establish that the animals had suffered unnecessary pain prior to death.

“It wasn’t simply enough to find dead dogs . . . it was a harder task than you may think,” said Moriarty.

Revelations of the killings arose in January 2011 after Fawcett filed to a claim to the BC workers’ compensation board, alleging he had developed post traumatic stress disorder from the slaughter.

The claim, which contained graphic descriptions of how Fawcett killed the dogs, was leaked to the media, prompting a massive outcry.

According to the B.C. SPCA, Fawcett also posted comments on a PTSD website about the killings, describing how the panicked dogs were shot or had their throats slit before being dumped in a mass grave.

Fawcett and his employer, Outdoor Adventures, claimed in a statement following the furor that the dogs had to be euthanized because they were too old, sick and not adoptable.

Fawcett said “considerable” efforts had been made to adopt the dogs before and after mid-April 2010.

But in his worker’s compensation documents, he instead he had to euthanize the animals after a downturn in tourism following the Olympics in February 2010.

A grisly exhumation of 54 sled dogs was performed in a seven-day dig in May 2011. Experts included entomologists, anthropologists and archeologists who had previously worked on other high-profile forensic investigations, including mass graves in Bosnia, Kosovo, East Timor and Rwanda.

The dig was difficult, even for cruelty investigators, who see animal cruelty in their day-to-day life, Moriarti said.

“This case, the scope of it, there were tremendous emotions involved. But you have to do what you have to do to bring this to justice,” she said. “Everybody put their heads down and worked to ensure the forensic evidence that was needed was presented.”

Following the killings, the British Columbia government brought in new protections for sled dogs, establishing legal requirements for issues such as containing animals, euthanasia, their health and working conditions.

Fawcett will make his first court appearance on May 24 in Pemberton. He faces a maximum of five years in jail, and could be subject to lifetime bans on owning animals.

The B.C. SPCA is planning a memorial for the slain dogs to be held this summer.

With files from Canadian Press