The Mora apartment building where three people died in a fire last week didn't have adequate smoke detectors, state authorities said Tuesday.

State Fire Marshal Jerry Rosendahl, who also said Tuesday that the fire is being initially considered accidental in origin, noted that the hard-wired smoke detectors in each of the four apartments were inoperative on the morning of Dec. 8, when the blaze erupted.

Each apartment also had a battery-operated smoke detector, Rosendahl added. However, three of the four were either removed or had the batteries taken out, leaving only one that may have been operational, he said.

"In every fire, our investigators look closely at the presence and operability of smoke alarms," he said. "Our statistics tell us that those alarms are a consistent, predictable contributor to survival in structure fires. Too often, however, we find smoke alarms are missing or damaged -- or the batteries have been removed for other use -- and that's just a chance that's not worth taking."

Mora Fire Chief Mike Anderson said Tuesday that the building would have been legally required to have working hard-wired smoke alarms in every apartment, if it had any electrical upgrading in recent years.

The property is owned by Allen and Melody Kadlec, who live elsewhere in Mora. Told of the safety shortcomings found by the state, Allen Kadlec would only say, "I'm not at liberty to comment at this time."

The fire's exact cause will not be known until the investigation is finalized. The blaze is believed to have started in the living room of one of the lower-level apartments.

Killed in the fire were Michael Caley, 48; his son, sixth-grader Coleman, and their neighbor Shirley Norling, 68.

Three others fled the fire. One of them was last reported to be hospitalized in the Twin Cities in critical condition.

The day of the blaze, Fire Chief Anderson said that at least one alarm was sounding in the building. Informed Tuesday of the building's inadequate alarm protection, Anderson said, "I heard [the morning of the fire] what I interpreted as at least one alarm going off at the time."

The Rev. Bob Bohachek, who lives within 30 to 40 yards of the building, said Tuesday that he and his wife heard no alarms that morning.

The apartments had no fire sprinklers, but the law requiring them took effect after the building was built, said state Department of Public Safety spokesman Doug Neville.

Paul Walsh • 612-673-4482