A fire, late Tuesday, ruined a $2 million, 5,800-square-foot home in the 9000 block of Northeast 28th Street that was under construction, and just one month from completion.

The home’s sprinkler system, which didn’t pass its final inspection, was unable to fight the fire.

“Firefighters arrived to find heavy flames throughout the first floor,” according to a press release from the fire department. “A partial collapse of the second floor made it difficult to fight the blaze inside the house.”

Neighbors reported it at 11:54 p.m. Tuesday night, and it took firefighters 1.5 hours to control it. Bellevue fire investigators believe that the fire originated in the floor-ceiling assembly between the first and second floor, and they believe that the causes were either electrical or mechanical.