A fire Sunday afternoon displaced tenants of an apartment building on Forest Avenue in Portland.

The cause of the fire, which started around 4 p.m., is under investigation but is not considered suspicious, said Portland Deputy Fire Chief John Everett.

About 10 people lived in four apartments in the building, which is also home to Brea Lu Cafe, Everett said. A woman at the scene said she knew the residents of the building and that they are college students.

Traffic was detoured off Forest Avenue as firefighters battled the fire at the corner of Forest Avenue and Pitt Street until after 7 p.m.

Everett said the department planned to return to the scene Monday to continue the investigation. No one was hurt in the fire, including two dogs that were rescued by firefighters.

He said the building will have to be inspected before anyone can move back in, but that damage was extensive because firefighters had to open walls and ceilings to make sure the fire was completely out.

That’s what took firefighters until past 7 p.m. before they could clear the scene, and they weren’t back at the station long before another call came in from farther down Forest Avenue at Princeton Pines Apartments.

There, a heat gun being used to thaw pipes started a fire when a squirrel’s nest in the wall began to burn. The damage was less severe there, Everett said, but residents also had to spend the night elsewhere.