Smoke inhalation killed two little Leamington girls and their dad when the trailer they were camping in exploded into flames early Monday, according to Essex police.

But it could be weeks before a cause is determined for the fire at Epping Forest Trailer Park on County Road 50 East in Essex.

"We don't have a cause yet because we are still looking at some of the potential ignition sources. We've taken some of the exhibits for further analysis," said lead investigator Tom Hutton with the Ontario Fire Marshal's office.

"I can't really nail down a timeline because we're still working on it right now. We have to examine those exhibits and see whether they contributed or they didn't."

Autopsies on the three victims were conducted Wednesday in London. Police said the medical examiner and the coroner also identified the remains of two victims, Cesario Dan Silva Leal, 34, and his 11-year-old daughter Raquel Ines Graca from Leamington. They still haven't positively identified the third victim. But family friend Paolo Fernandes confirmed it was Leal's five-year-old daughter Carolina.

Police said the cause of the fire was still under investigation, but added they don't suspect foul play.

Fernandes said a funeral for Leal and his girls will take place Saturday at 10 a.m. at Reid Funeral Home in Leamington.

Hutton said the flames likely spread through the interior of the trailer quickly. "A trailer of that size, with the confined space -- it's not going to take the fire very long to spread," he said.

"There's woods, there's plastics. You have upholstered furniture in there, in the way of a foam mattress."

The first people at the scene of the fire were other park residents, who attempted to put out the flames with garden hoses. They also tried to cool the trailer's propane tank.

Hutton said the chances of an explosion were minimal, since most propane tanks have a safety valve that releases the contents when there is a danger of explosion.

Hutton said no propane release occurred with the trailer in question.

Asked when he estimates he will complete his report on the incident, Hutton replied: "It's probably going to be a couple of months."

Meanwhile, the Ontario Fire Marshal's office is stressing that trailers and RVs are not exempt from the provincial fire code that makes smoke detectors a mandatory safety measure.

"If your trailer functions as a home, as a dwelling unit, then you are required to have a working smoke alarm," said Al Suleman, a fire protection engineer with the OFM.

"That includes seasonal homes such as park model trailers, cabins, cottages, and for the most part it includes motor homes and recreational vehicles when they are used as dwelling units."

Essex fire chief Ed Pillon said there was no sign of a working smoke detector in the trailer in question, and the presence of one might have prevented the tragedy.