Fire investigators said not enough evidence was found to determine what started an early morning fire at a Kakaako condo unit last week, and the cause is being classified as undetermined.

Thirty-nine firefighters responded to the two-alarm fire at 12:03 a.m. Friday on the sixth floor of the 43-story Keola Lai Condominiums at 600 Queen St.

An automatic fire sprinkler doused the fire, and one resident sustained a lower leg injury while evacuating the building, according to Honolulu firefighters. An adult, female resident alerted by a smoke alarm was able to escape the unit without injuries.

Fire investigators said the exact location and manner in which the fire began could not be determined. Fire damages are estimated at $20,000 to the structure and $5,000 to its contents.