Fire investigators have found that a Chinatown fire that caused moderate damage to portions of Indigo Restaurant Tuesday night, was caused by an electrical malfunction in a wall outlet.

The Fire Department said the fire started accidentally in an employee lounge at Indigo, located at 1121 Nuuanu Ave. in the McLean Building.

When firefighters arrived at the 11:24 p.m. fire, they found heavy smoke from the Nuuanu Avenue and Bethel Street sides of the building, and the fire had broken through the ceiling and had begun to spread through the attic.

The fire was brought under control by  12:03 a.m. and extinguished at 12:38 a.m.

Fifty-five firefighters fought the blaze and were able to confine it to Indigo’s employee lounge, an adjacent storage room, and light damage to its office. There was no damage to the first floor restaurant.

No one was present at the time of the fire.

Damage is estimated at $100,000 to the structure and contents.