The Sheriff's Department, which is investigating the shooting, says the victim and two others arrived at a home on Limon Lane in El Cajon and were met inside the house by two men and a woman.
According to investigators, there was some sort of an altercation before the shooting took place.
"I was asked if homeowner discovered people when he came home, that is not what happened," said Sgt. Tim Chantler with the San Diego Sheriff's Department.
Sgt. Chantler ruled out robbery as a motive and said there was no drug manufacturing going on at the time of the shooting, although in the past, deputies have responded to the house on drug calls and removed a stolen vehicle parked at the property.
So far, no one was been arrested in connection with the shooting.
As of Monday evening, five people were being questioned about the incident.