Police said they suspected the incident as a murder-suicide.
Orange police Sgt. Dan Adams said police officers found the bodies in an apartment Tuesday afternoon after the manager of the apartment reported that he had not seen or heard from his tenants for several days.
Adams identified the victims as a 44-year-old man, a 42-year-old woman and their young son about two or three years old.
The three were declared dead at the scene, the sergeant said. Their names were withheld pending family notification.
Adams said it appeared that all three had been shot by the man, who had a small caliber handgun next to his body. Also found at the site was a suicide note the man is believed to have written, he said.
The contents of the note were not immediately disclosed.