The Red Cross provided emergency assistance to the four families who were displaced.

Chopper 7 video showed smoke pouring from the complex just off the Sumner-Enumclaw Highway at about 6:30 a.m.

Video: Early Morning Fire Destroys Bonney Lake Home

"When I got here, the flames were up to the trees, so it was pretty, pretty dramatic," said Dave Enslow, the owner of the complex, who got a call about the fire at about 4:30 a.m.

There was heavy fire damage to one unit and smoke and water damage in the others.

The fire started in a unit that was not occupied and spread to attached apartments through the attic. Investigators were combing the ashes for clues as to what started the fire.