The child was discovered shot to death, along with a man and a woman, around 11 a.m. Tuesday at a home in the 9500 block of High Park Lane. Officers arrived at the scene, after a family friend called police, saying they hadn't heard from the family that lived there in a few days.
Officers found the body of the woman in the kitchen. The man and the young boy were found dead upstairs. All of the victims had gunshot wounds to the upper body, according to San Diego Police Department Lt. Paul Rorrison.
The names of the victims have not been released and so far investigators believe the man shot the other two, then himself.
The identities of the victims have not been released.