There remain more questions than answers now that the Ontario Fire Marshal has wrapped up its on-site inspection of the fire that destroyed a barn at Classy Lane Stables in Puslinch on Monday.

Inspectors gathered their equipment and left the scene Thursday afternoon, returning the property to owner Jamie Millier.

But what caused the fire is still unknown.

"We know a lot of people would like to have an answer to what transpired," said Wayne Romaine, a supervisor with the Fire Marshal. "Unfortunately, the fire was able to develop and burn for a substantial amount of time. That impacts on our ability to try and determine a cause."

Romaine confirmed that 43 animals died in the fire, including 39 standardbred horses, three ponies, and one thoroughbred horse.

He said the roof of the barn collapsed into the structure during the fire, killing the animals and causing a significant amount of damage. He and his inspectors had to delicately pick their way through the wreckage to find the evidence that survived.

"We've been sifting and searching and using small hand tools as we focus in on areas of interest for ourselves," he said.

Despite the difficulty, Romaine is confident his office will be able to classify this fire, either as undetermined, accidental or the result of human intervention.

"Hopefully that will be important to everyone concerned," he said, but cautions that the final report on the fire will not be made public for another three to four months.