OKLAHOMA CITY - Fire crews now have a fully-involved fire at a four-plex in southwest Oklahoma City under control.

Oklahoma City firefighters were called to 3300 S. Kentucky Avenue just before 10 a.m. There were several calls about heavy smoke in the area.

When firefighters arrived, they found flames and smoke shooting from the four-plex. Fortunately, everyone escaped from the structure. There are no reports of injuries.

However, fire investigators are still looking for the people who were inside the home at the time of the fire.

The property owners say no one was living there and no one should have been inside the building. In fact, no utilities were hooked up to the house, but neighbors say people - including children - were staying there overnight. Apparently they all ran from the house after the fire started.

Because of the intense heat, firefighters took frequent rest and water breaks to ensure they didn't suffer from heat stroke.

It's not known yet what caused the fire.