The search to determine the cause of the fire that destroyed a high-end horse stable in Puslinch will be a thorough and difficult process, investigators said Wednesday.

Thorough, because they want to make sure not a single piece of potential evidence is missed – and difficult, because the amount of destruction the barn endured likely eliminated a number of clues.

“That which you could have maybe identified at a certain stage in the fire’s department now is completely consumed, or is maybe a plastic globule that’s not identifiable,” Wayne Romaine of the Office of the Fire Marshal told reporters.

Romaine said that investigators would start by trying to figure out exactly where in the barn the fire began, then focus on examining and talking to others about that area to determine a potential source of ignition.

“We simply don’t know (the cause) at this point in time,” he said.

A total of 43 standardbred race horses were killed in the fire, which broke out late Monday night at Classy Lane Stables.

Word of the fire spread quickly through Ontario’s horse racing community, and people with ties to the horses – many of whom live near the stable – quickly flocked to the scene.

By Wednesday afternoon, others who knew the horses were still making their way to Classy Lane to see the damage for themselves.

“I’ve never experienced anything like this in my life, and I wouldn’t wish it upon anybody to experience what we did Monday night,” horse trainer Nick Gallucci told CTV News.

“There’s no way you could ever plan to even imagine getting past this.”

At least 20 people are in search of new jobs due to the fire, as they made their livelihoods working with the horses in the barn.

One of the horses, Whistle Jimmy K, was driven by Scott Young.

“You just think you’re going to see him again next Friday. You find out he’s in that barn, and it’s just terrible,” Young said of his reaction to learning about the fire.

Those sentiments are shared by Gallucci, the first person to spot the fire, who described it as another blow for Ontario’s harness community.

“I can’t imagine waking up one day and not having a barnful of horses to look after and train,” he said.

Late in the day Wednesday, a spokesperson for the fire marshal’s office said that the on-site investigation would likely wrap up by 11 a.m. Thursday.

Damage from the fire is expected to top $5 million.