The Honolulu Fire Department investigators completed their investigation, but were unable to determine a cause of Wednesday’s Nuuanu apartment building fire, which displaced the building’s nine residents and killed a puppy.

The fire caused an estimated $300,000 in damage to the structure and $60,000 to contents at 23 Iliahi St.

Three people and a dog escaped from the building uninjured.

The undetermined classification means the fire investigator analyzed all possible causes, but there is insufficient information to identify a specific cause and insufficient information to eliminate some or all other possible causes.

HFD reminds the public to have a working smoke detector to increase chances of survival from a fire by more than 50 percent.

In a separate case, investigators determined that an Aiea building fire on Thursday was caused by a malfunctioning electrical outlet.

The fire department responded with nine units to 98-205 Aiea Kai Pl.

The fire caused an estimated $30,000 in damage to the structure and $20,000 to its contents.

No one was injured in the fire.

The fire department reminds homeowners to call a qualified electrician when blowing fuses or tripping circuit breakers are frequently occur, or when one experiences a tingling feeling after touching an electrical appliance, or if wall outlets spark or are discolored or warm.