Orange County Fire Authority Capt. Steve Concialdi said the boy was expected to survive the predawn attack Sunday at the San Juan Capistrano home.
Sheriff's Lt. Jeff Hallock told the Orange County Register (http://bit.ly/1fRPdhj) investigators have not identified a suspect or motive for the attack, and didn't know whether someone targeted them or entered the home randomly.
The victims' identities were not immediately released.
Neighbor Patty Bonin told the newspaper the dead were a married couple who owned a business in the community.