T

he cause of Saturday’s fatal Dinkytown fire will likely remain a mystery, Assistant Fire Chief Ulie Seal said Wednesday.

But Seal said investigators know the fire began on the porch, possibly because of careless smoking.

He said tenants were seen smoking on the porch the night of the fire, but investigators were unsure how close to the time the fire began.

Second-year students Elizabeth Wencl, 20; Amanda Speckien, 19; and Brian Heiden, 19, all died in the blaze early Saturday morning in their duplex at 827 15th Ave. S.E.

Seal said the investigation will remain open, but the cause is unlikely to be determined.

Investigators have ruled out electrical malfunctions and problems with the hot water heater as possible causes, but Seal said arson is still a possibility.

He said while there is no evidence the fire was intentionally set, the porch area was not secured and was easily accessible.

“It is a possibility, although we have no evidence to support it at this time, that someone could have wandered onto the porch and started the fire,” Seal said.

He also said investigators were unsure if any fire accelerants were used.

Despite witness reports of an explosion, Seal said explosion noises were most likely from a flashover, which is caused from a buildup of super-heated smoke and gases that ignite suddenly.

“This can sometimes blow windows out and create the appearance of an explosion,” Seal said.

Eischens Management is also clear of negligence at this point in the investigation, Seal said.

All three levels of the unit contained smoke detectors, and although there is no direct confirmation they worked at the time of the fire, Seal said he is certain they worked in August before the victims moved in.

Under city regulations, the single front exit in the duplex was adequate for the number of people living in the house.

Eischens Management spokesman Pat Brink said the company is satisfied with the fire department’s investigation.

“First of all, Eischens Management wants to express their heartfelt condolences,” Brink said. “Secondly, the Minneapolis Fire Department has ruled out a problem with either the water heater or the electrical system.”

He said while the uncertain findings might not be ideal, it is important to note Eischens Management is not to blame.

“Although it would have been helpful for everyone if the exact cause of the fire could have been determined, we believe the findings of the Minneapolis Fire Department confirm that no defaults in the property caused the fire.”