WEBSTER CITY — Investigators are still trying to figure out what caused a Wednesday night fire in Webster City that killed one man and left a woman in critical condition.

Webster City Fire Chief Charles Stansfield said Friday that investigators are still working. But he also raised the possibility that the cause of the blaze may never be discovered.

”I think it’s going to lean toward undetermined, but it’s still under investigation,” Stansfield said.

Fire investigators do know that the blaze at 603 Ohio St. started on the second floor of a two-story house that had been converted into apartments. There was one apartment on the first floor and one apartment on the second floor.

The names of the man and the woman have not been released by authorities. Officials have confirmed, however, that the man died.

Authorities have also said that the woman was initially treated at Van Diest Medical Center in Webster City before being airlifted to the University of Iowa Hospitals and Clinics in Iowa City, where she is listed in critical condition.

The fire was reported shortly before 11 p.m. Wednesday.

Stansfield said the people were pulled from the apartment and the fire was out within about 20 minutes.

He said the damage was confined to the second floor apartment.