Bellingham police arrested a 57-year-old man they say started the fire destroying the Hohl Feed and Seed store.
The fire engulfed the building in the early morning hours on Monday, Feb. 18.
Investigators determined the fire started inside a brick chimney in an alley behind the store. Police obtained surveillance video last week that captured several people enter the alley and the fire start shortly after they left.
The suspect denied intentionally setting the fire, according to police.
Police questioned a second suspect identified in the surveillance video who said the primary suspect started the fire for warmth.
According to police, he was arrested for "reckless burning in the first degree for starting a fire on private property that led to building damage."
The Whatcom Humane Society cared for the animals rescued from the fire.
Now, the small critters are available for adoption. The humane society planned an adoption event for Saturday, March 2 between 2-5 p.m.
Rabbits, rats, hamsters, gerbils and mice that survived the fire will be on hand. Interested adopters get to name their own adoption fee.
Clark Feed and Seed, another pet shop next door, was also damaged.
Hohl Feed and Seed was in operation for more than 40 years and was the oldest "continually operated retail store" in Whatcom and Skagit counties, according to its owner, Larry Oltemann.
The Bellingham Fire Department responded to the 911 call around 4:30 a.m. Firefighters poured 6,000 gallons a minute onto a pair of burning structures, which were built in 1902 and 1910.