Durham, N.C. — Fire investigators have reversed their initial finding and are now looking into the likelihood that a fire at a Durham apartment complex last week was set.

The fire broke out Thursday morning at the Royal Oaks Apartments, at 3545 Mayfair St. Ten units were damaged, displacing 14 adults and six children.

Two firefighters fell into the basement through a hole in the first floor while battling the blaze, and one suffered minor injuries, authorities said. No other injuries were reported.

Investigators initially said they didn't believe the fire, which started in the basement, was a case of arson. On Monday, a Durham Fire Department spokeswoman said authorities were investigating the case as a possible arson.

A juvenile was charged with setting an Oct. 6 fire at the apartment complex. The complex also was the site of a fire in the summer of 2006, authorities said.