DURHAM, N.C. — Durham fire investigators say they have a solid lead in the case involving two fires at an apartment complex in Durham this week.

Investigators say that after talking to witnesses, they now have an active investigation under way and are working double time to solve the case because they are afraid another fire could happen.

"It's a bit unsettling," said Brieann Valdiviezo, a resident of the apartments.

Since Sunday, residents at the Azalea Park apartments have awoken twice to the smell of smoke and sound of sirens.

"We've all been victims of the fires; whether we actually lost something or not, we're all victims," Valdiviezo said. "I'm up several times during the night. I look out the door to see if I see flames or smell smoke."

Investigators say in both cases the fires were set in outside stairwells.

The SBI is testing samples taken from the scene to see if there was an accelerant. In the last 24 hours, Durham police and sheriff's deputies stepped up patrols in the area.

The community is also putting its best foot forward. From Christmas trees, to clothes and toys... strangers are reaching out to strangers with donations.

"It's Christmas ... and we thank you for helping," said a tearful Valdiviezo.