Oklahoma City fire crews battled an apartment building fire early Sunday morning.
Just before 4:00 a.m., crews responded to a commercial fire alarm at 3500 S. Walker. Upon arrival, firefighters encountered very heavy fire coming from a quad-plex.
The fire was initially attacked from the inside, but a roof collapse and heavy fire conditions prompted firefighters to pull out and fight the fire from the exterior.
After the fire was contained, it was determined the building was vacant. The quad-plex east of the building had four people inside and they all made it out safely.
Investigators are on scene to determine the cause of the fire.