The search for the cause of the fire at the N. Ninth Street apartment in Cambridge continues

Cambridge fire investigators are continuing to search for the cause of a blaze on Monday that caused moderate damage to an apartment building that seven people called home.

“The cause remains under investigation,” Fire Chief Jeff Deeks said Tuesday.

Firefighters reported a power line outside the house was on fire when they arrived on the scene just after 10 a.m.

Witness testimony and reports from first responders confirmed that an electrical service line on the south exterior wall was on fire when black smoke was first visible coming from the three-apartment structure.

Cambridge police responded that they had been told there were people upstairs who were ‘trapped because of the fire which appeared to be on the outside wall of the stairwell going up to the ‘stage”.

Patrolman Adam James said in his report that there were “pops that sounded like something electrical” in his report.

The trapped residents who were rescued by firefighters using the city’s ladder truck were identified by police as Amy Clair and Noah Craft.

Residents were removed from a second story window and lowered to the ground where they were examined by United Ambulance medical staff for smoke inhalation.

Initial reports said one of the residents was “hanging out of a window” on the second floor before being rescued.

After:Cambridge firefighters rescued four people from an apartment fire, heavy smoke was reported in the building

A third upstairs resident, Matthew Craft, was able to escape unharmed using the stairs.

Police say Matthew told them he smelled smoke and an unidentified woman across the street alerted him to the fire when he looked out the window. He also reported seeing the fire on the outside wall and hearing “popping” sounds common with an electrical fire.

The popping noises are attributed to the electric arc.

Two people believed to have been asleep at the time of the fire and the other unidentified residents were able to exit the home unharmed on the ground floor of the structure at the corner of North Ninth Street and Gomber Avenue.

A dog rescued from the building was taken to a local veterinarian for treatment for smoke inhalation. The dog was reportedly accompanied by its owner, but no information regarding its condition was available.

Cambridge firefighters launched an initial exterior attack on the blaze before moving inside to douse flames that had spread to the attic and part of the third floor.

Once the flames were extinguished, firefighters began overhaul efforts, including checking for hot spots that lasted all morning.

Firefighters then used the ladder truck to punch a hole in the roof to ventilate the fire and smoke.

“Fire damage to the first and second floors was minor, but the third floor apartment, closer to the main source of fire, suffered more extensive damage,” Deeks said. “The entire residence suffered smoke and water damage.”

Deeks said the fire was not suspicious in nature and foul play was not suspected.

The chief credited city police officers with assisting firefighters and limiting traffic access to the area during the initial response to the call. Cambridge street workers also helped with traffic control.

No injuries were reported by first responders.