SAN DIEGO (CBS 8) - Firefighters are investigating the cause of a Bay Park apartment fire.

It broke out just before 3:00 a.m. Saturday morning at a complex in the 2900 block of Clairemont Drive.

The fire started on a patio and quickly spread to two apartments. Fire officials say families living in two of the units have been displaced, including three adults and one child. They are currently receiving aid from the Red Cross.