DURHAM, N.C. — Arson investigators spent Friday at a burned-out apartment complex in Durham. A fire Thursday night destroyed more than a dozen units at the Innesbrook Apartments off Fayetteville Road. Investigators know where the fire started, but they haven't determined a cause.

Investigators said the blaze started on the outside of the buildings and then burned up the walls to the attic. With a nose for accelerants, a State Bureau of Investigation arson dog sniffed around the central staircase. He hit on a couple spots.

Investigators collected samples that they'll take to the lab for more tests. At this point, they won't way what that means, but they're not ruling out any causes.

However, Tasha Evans has her suspicions. She lived in one of the 16 apartments destroyed by the fire. She said three times in the last month, she saw people sneaking around the building.

"Breaking into cars, breaking into apartments," said Evans. "I called police every time I (saw) people come out here."

Evans was home yesterday when the fire started.

"I went to the front door," she said. "I saw black smoke and I heard crackling and fire. It looked like it was coming through the front door, so I ran back to the kitchen."

Evans called 911 and escaped her ground-floor apartment by going out her patio door as firefighters arrived.

Even while firefighters were battling the flames, others were already looking for clues. Still, Durham Fire Marshal Edward Reid stressed there could be any number of causes.

"We're not ruling out if the fire was started by someone or an accidental cause," said Reid.

It could be days before SBI has results back from the samples taken at the complex.