BUFFALO, N.Y. - Firefighters say furniture that was burning outside of a 10th Street home caught the rest of the building on fire.

It happened just before 8:30 a.m. Sunday.

When fire crews arrived, they saw heavy flames traveling up the left side of the building and reported heavy fire in the attic. They were worried there may have been people still inside, and they were concerned the fire was going to spread next door because the homes are so close together.

The building is a two-family home. Neighbors alerted the people living downstairs, and they were able to get out safely.

There was no one living upstairs.

"We never know the status of buildings when we pull up. We have to figure it out. What we learned was the second floor was in the middle of being moved in or moved out, so even thought it appeared as an occupied house, there was nobody up there," said Buffalo Division Chief Peter Kertzie.

Firefighters estimate there is roughly $35,000 in damage to the home and $10,000 damage to the contents.

They are still trying to determine what caused the fire.