SHORELINE, Wash. -- Investigators say a three-alarm fire at a vacant furniture store in Shoreline is arson.

The fire erupted just before midnight Thursday at North 170th Street and Aurora Avenue North in Shoreline. It raged for hours overnight and was still smoldering Friday morning.

Firefighters arrived to find the rear of the building fully involved in flames and smoke visible for miles. At one point firefighters had to pull back from their position on top of the building after the roof began to collapse.

Flames shot 20 to 30 feet into the air and destroyed the vacant store. Firefighters were able to protect nearby businesses and property.

SLIDESHOW: Fire Rages At Shoreline Complex
UNCUT: Shoreline Fire Burns Overnight

KIRO 7 News reporter Jeff Dubois said the fire started in the back of the NW Discount World store. The old building had no firewalls or sprinkler system to stop the flames.

The blaze closed Aurora Avenue North between 165th and 175th streets. Firefighters opened the southbound lanes at around 7 a.m.

Arson investigators are at the scene to determine if there's any connection between this fire and more than a dozen that erupted in Seattle's Greenwood area. Investigators are also looking into the possibility that a recent fire, also in Shoreline, may be connected to those arsons.

Kevin Todd Swalwell was arrested in Shoreline shortly after the blaze broke out at the store and remains a person of interest in the fire. However, he is considered a suspect in the string of arson fires in Greenwood. Read Story.

Seattle police said Swalwell was arrested approximately 10 blocks from the Shoreline fire incident around 12:30 a.m.