ANAHEIM, CA -- The investigation continued Sunday into what caused a four-alarm fire inside an apartment complex that left 22 units damaged, three people hospitalized for smoke inhalation and 80 people displaced, a public safety spokesman said.

The fire broke out inside an apartment complex at 225 S. Rio Vista St. at about 8 p.m. Saturday, according to Anaheim Police Sgt. Daron Wyatt.

The fire burned several units and was quickly upgraded to a four-alarm blaze, according to the department.

Two adults and one child suffered mild smoke inhalation and were taken to a hospital for treatment, Wyatt told City News Service.