BREWER – A barking dog alerted residents in a multifamily apartment building at 121 Parker St. that there was an emergency last month.

The Sept. 22 fire destroyed the entire back of the dwelling, displaced three families living there and killed three pets – two cats and a dog.

It is not known whether the hero dog is the one that perished, but police have arrested the man they suspect started the fire.

Brian Pelletier, 25, was arrested at his Bangor home around 8 p.m. Oct. 25 after an arrest warrant charging him with arson was issued from the Penobscot County Superior Court. He was taken into custody by Brewer Detective Sgt. Jay Munson and Stu Jacobs, State Fire Marshal’s Office investigator.

Pelletier was taken to the Penobscot County Jail, and had his initial court appearance Friday when his bail was set at $2,000.

The September fire, reported just after 6 a.m., burned through the back walls of all three family apartment units, and smoke and water damaged the sides of the building.

The building was occupied at the time of the blaze by five adults and two children, but none of the residents was severely injured. One was taken to Eastern Maine Medical Center in Bangor and released later that day.