Investigation underway following early morning fire at Oconomowoc restaurant Fiesta Cancun

OCONOMOWOC, Wis. (CBS 58) -- An investigation is underway following an early morning fire at well-known Oconomowoc restaurant Fiesta Cancun. 

Officials with Western Lakes Fire District were dispatched to the restaurant around 3:05 a.m.

Officers on scene reported heavy black smoke coming from the back of the building, and a full response was initiated from the district's six stations.

Western Lakes says crews were temporarily evacuated from the building just before part of the roof collapsed. 

Officials say one family from the upper-level apartments was evaluated for smoke inhalation.

There were no other injuries reported. 

This is a developing story. Stick with CBS 58 for updates on-air and online.