By CBS 2 Chicago Staff

STONE PARK, Ill. (CBS) — Investigators believe a fire that destroyed four apartment buildings in Stone Park this weekend started on a wooden back porch.

The fire broke out Saturday afternoon in the 1800 block of 36th Avenue, south of North Avenue, in Stone Park. A total of four buildings and 12 units were destroyed, and people at the scene said more than 20 people were displaced.

A view from overhead shows the devastation – four apartment buildings in Stone Park were destroyed, each of them with three units.

A dozen families – some with young children – were left homeless.

The apartments were so badly damaged that they are not inhabitable.

Investigators said it is likely a smoke detector saved lives.