PHOENIX -- Investigators are trying to determine what sparked a fire that tore through a vacant apartment complex in Phoenix Wednesday morning.
It happened at about 4 a.m. in the neighborhood of 10th Avenue and McKinley Street.
While the building had been abandoned, transients reportedly were living in a back room. Investigators believe those people started a fire to keep warm overnight.
A fence surrounds the now-gutted building, which made it difficult for firefighters to do their job. In addition, the doors and windows were boarded up, blocking crews' access.
Flames were shooting through the roof about 30 feet into the air when firefighters arrived.
Their first priority was to make sure the vacant structure was actually empty. They did not find anybody.
No injuries were reported.