The blaze, in the unit block of Broadleaf Drive in Belltown Woods, was instead caused by an electrical wiring problem, investigators have ruled.
The fire started shortly before 4:00 p.m. in a two-story home.
The occupants were not inside when the fire started. The fire was called in by a neighbor.
No one was hurt and the fire was brought under control within 45 minutes.
Damage was estimated at approximately $300,000.
Lightning was initially suspected because the fire started during Sunday's thunderstorms.
