An accelerant sniffing dog from Spokane Valley spent the morning walking through the wreckage of the Queen of the River mansion in Post Falls Friday.

Mako, an accelerant sniffing dog that is a member of the Spokane Valley Fire Department, was at the home Friday morning as investigators are looking into why the home burned to the ground early Thursday.

The black lab, bought and trained with money from State Farm, alerted on a half dozen spots inside the home's interior that smelled like petroleum. The problem is smelling petroleum and determining if what Mako found could be two different things.

"Those dogs are trained to sniff petroleum products and so we live with petroleum products around us every day, plastics, everything," Division Chief Dan Ryan with the Kootenai County Fire Department said.

In addition to having Mako comb the debris, investigators also began removing debris samples from the home. Those samples will be studied for the presence of hydrocarbons such as petroleum-based products.

"The dog alerted on a couple places and we were not able to determine what it was so we'll take some samples, send it to the lab and they'll tell us what it is," Ryan said.

The property overlooking the Spokane River is now being treated like a potential crime scene, and the investigation has become a joint fire / police operation with members of the Post Falls Police Department, Kootenai County Fire Department and Spokane Valley Fire Department participating in the effort.

Also assisting in the case is a State Farm representative; State Farm carried the insurance policy on the home. That representative is working alongside fire investigators to determine if the fire was accidental in nature or intentionally set.

"Working with the insurance company and the police department there's going to be some security on this over the weekend and then Tuesday there will be some more resources available to us to help us with the investigation so we can go a little bit further," Ryan said.

Division Chief Ryan said nothing so far has told them this fire is anything more than suspicious in nature.

"What it tells us is we have a lot more work to do; that we need to do some more digging starting with the point of origin and then narrow it down, hopefully to a cause," he said.

Homeowner Len Wallace, who was at the home Thursday morning, was not at the scene Friday.

The investigation into the fire at the Queen of the River comes on the day that the house had been scheduled to be foreclosed on, according to a 2011 bankruptcy filing by Wallace. If the fire is determined to be arson set it could be more difficult for the owners to collect on their homeowners insurance policy.